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CICS Executive Board, Fellows and External Principal Investigator Bios CICS Executive Board Members Isaac M. Held, GFDL Senior Research Scientist Hiram Levy II, GFDL Senior Research Scientist Denise L. Mauzerall, Assistant Professor of Public and International Affairs Michael Oppenheimer, Professor Geosciences and Public and International Affairs Stephen W. Pacala, Professor of Ecology and Evolutionary Biology S. George H. Philander, Director of AOS and Professor of Geosciences V. Ramaswamy, GFDL Senior Research Scientist Ignacio Rodriguez-Iturbe, Professor Civil and Environmental Engineering Jorge L. Sarmiento, Director of CICS and Professor of Geosciences Geoffrey K. Vallis, Associate Director of CICS and Senior Research Oceanographer CICS Fellows Lars O. Hedin, Professor of Ecology and Evolutionary Biology and Princeton Environmental Institute Sonya A. Legg, Lecturer of Geosciences and Research Oceanographer in the Program of Atmospheric and Oceanic Sciences Michael Oppenheimer, Professor in Geosciences and International Affairs, Woodrow Wilson School Stephen W. Pacala, Professor in Ecology and Evolutionary Biology, Acting Director of Princeton Environmental Institute S. George H. Philander, Professor in Geosciences, Director of the Program in Atmospheric and Oceanic Sciences Ignacio Rodriguez-Iturbe, Professor in Environmental Sciences, Professor of Civil and Environmental Engineering Jorge L. Sarmiento, Professor of Geosciences, Director of CICS Daniel M. Sigman, Assistant Professor of Geosciences Eric F. Wood, Professor of Civil and Environmental Engineering External Principal Investigators Dale B. Haidvogel, Professor at Rutgers University Thomas W. N. Haine, Professor at Johns Hopkins University George C. Hurtt, Professor at the University of New Hampshire Eli Tziperman, Professor at Harvard University Charles J. Vörösmarty, Professor at the University of New Hampshire Dale B. Haidvogel Dr. Dale B. Haidvogel is a Professor of Marine Sciences at the Institute of Marine and Coastal Sciences of Rutgers University, New Brunswick, New Jersey. After completing his doctoral studies at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution (MIT-WHOI Joint Program) in 1976, he pursued postdoctoral studies in the Center for Earth and Planetary Physics of Harvard University. Since that time, he has held professional appointments at WHOI (1978-1982), the National Center for Atmospheric Research (1982-1986), the Johns Hopkins University (1986-1990), and finally Rutgers University (1990present). Dr. Haidvogel's primary research interests include the development of advanced algorithms for geophysical modeling (e.g., high-order finite element and finite volume methods; see Choi et al., 2004, Mon. Wea. Rev., 132, 1777--1791), the coupled modeling of regional climate impacts (e.g., the ecosystems of the Northeast Pacific; Hermann et al., 2002. Prog. Oceanogr., 53, 335--367), numerical and laboratory studies of fundamental processes (e.g., flow-topography interaction; see Curchitser et al., 2001. J. Phys. Oceanogr., 31, 725--745 and Boyer et al., 2004, J. Phys. Oceanogr., 34, 1588--1609), ocean observing systems and data assimilation (e.g., in the Northwest Atlantic; see http://marine.rutgers.edu/mrs/), quantitative metrics for ocean model performance (see http://marine.rutgers.edu/po/index.php), and the promotion and distribution of ocean modeling systems and products (http://www.ocean-modeling.org/). Dr. Haidvogel has participated in the scientific planning and/or execution of many large-scale, multiinstitutional and international oceanographic programs of the last three decades, including the Mid-Ocean Dynamics Experiment (MODE, PolyMODE), the World Ocean Circulation Experiment (WOCE), and most recently the Global Ocean Ecosystems Dynamics project (GLOBEC). He has served on the Scientific Steering Committees for U.S. WOCE and U.S. GLOBEC, and is currently Chair of the U.S. GLOBEC SSC. He was Co-Editor of the journal Dynamics of Atmospheres and Oceans from 1980 until 2005. Dr. Haidvogel founded and directs the IMCS Rutgers’ Ocean Modeling Group, which has as one of it foremost goals the development, verification and interdisciplinary application of new regional and basinscale ocean modeling systems, including coupled models for (e.g.) atmosphere/ocean, biogeochemical, and/or ecosystem response. Modeling software developed by the Ocean Modeling Group, and its colleagues, has been distributed worldwide to approximately 1000 scientists. Thomas W. N. Haine Dr. Thomas W. N. Haine is an Associate Professor in the Department of Earth & Planetary Sciences at Johns Hopkins University in Baltimore, MD. Research Interests & Accomplishments: My research is in the physics of the basin-scale ocean and its role in Earth's climate. I am involved in improving estimates of the geophysical state of the ocean circulation through analysis of field data and circulation model results. The subpolar North Atlantic ventilation process (rates, pathways, variability, and mechanisms) interests me in particular. I also investigate key physical processes that maintain the state of the extra-tropical upper ocean focusing on fluid dynamics and thermodynamics and their role in controlling sea surface temperature variability over years to decades. In particular, my current research projects are to: Identify and understand the tracer-independent transport information contained in ocean tracer data. Identify and understand the dynamic and thermodynamic mechanisms controlling midlatitude interannual SST variability. Improve understanding of the circulation and dynamics of the Denmark Strait, East Greenland Shelf, and Irminger Sea. Understand the dynamics of rotating stratified fluids in laboratory experiments involving nonlinear interactions. These projects are currently sponsored by the National Science Foundation, National Aeronautics and Space Administration, Johns Hopkins University, and the National Oceanic & Atmospheric Agency. In the last three years I have advised 8 graduate students and 3 post docs. I have received many invitations to speak in seminar series, at workshops, and in short courses. I have published about 20 articles in the scientific literature during this time. I was also an invited participant at the National Academy of Sciences, US Frontiers of Science Symposium, an Invited Visiting Professor at Catholique Universite de Louvain-la-Neuve, Belgium, and am listed in Who's Who in the World, Who's Who in America, and 2000 Outstanding Intellectuals of the 21st Century. Lars O. Hedin Dr. Lars O. Hedin is a Professor in the Department of Ecology and Evolutionary Biology and the Princeton Environmental Institute at Princeton University,NJ. He has held faculty positions at Cornell University and Michigan State University. Dr. Hedin's research focuses onunderstanding natural ecosystems as complex biogeochemical systems, with emphasis on evolutionary implications for plant and microbial communities. He has received the Mercer Award from the Ecological Society of America for his work on developing "baseline" understanding nutrient cycles in pristine South American forests, against which mechanisms and extents of human impacts can be interpreted. He has for over a decade studied remote forests in southern Chile and Argentina, and, more recently, tropical forests in the Hawaiian archipelago, the Amazon, Central America, as well as forests in New Zealand. Dr. Hedin recently chaired a white paper report on "Challenges to Linking Ecological Biology and Geosciences" to the National Science Foundation (NSF), and is one of the founders of the biogeosciences section of the Ecological Society of America. He has published over 40 peer-reviewed articles in journals including Nature, PNAS, Scientific American, Ecology, and Global Biogeochemical Cycles, and his findings have been broadly covered in the scientific and public media. Isaac M. Held Dr. Isaac Held is a Senior Research Scientist at NOAA's Geophysical Fluid Dynamics Laboratory, where he conducts research on climate dynamics and climate modeling, and is head of the Weather and Atmospheric Dynamics Group. After receiving his Ph.D. at Princeton University, and after a short stint at Harvard University, he joined GFDL in 1978 and has remained there ever since. He is also a lecturer with rank of Professor at Princeton University, in its Atmospheric and Oceanic Sciences Program, where he has supervised over a dozen Ph.D. theses. He also serves as an Associate Faculty member in Princeton's Applied and Computational Mathematics Program and in the Princeton Environmental Institute. Dr. Held is a Fellow of the American Meteorological Society (1991) and the American Geophysical Union (1995), and a member of the National Academy of Sciences (2003). He has received the Meisinger Award of the AMS (1987) for "outstanding contributions to the study of climate dynamics ....", the Bernhard Haurwitz Memorial Lectureship of the AMS (1999), the Rosenstiel Award from the University of Miami (1994) "for breadth and incisiveness is attacking fundamental problems of geophysical fluid dynamics, the general circulation of the atmosphere, and climate dynamics", the Department of Commerce Gold Medal (1999) "for world leadership in studies of climate dynamics", the NOAA Presidential Rank Award (2005). George C. Hurtt Dr. George Hurtt is an Assistant Professor in Community and Ecosystem Ecology at the University of New Hampshire. He earned a B.A. in Biology from Middlebury College in 1990. His advanced degrees are in Ecology and Evolutionary Biology. In 1992 he received a M.S. from the University of Connecticut. In 1994 he received a M.A., and in 1997 a Ph.D., from Princeton University. He was a Postdoctoral Fellow at Princeton prior to joining the faculty at the University of New Hampshire in 1998. Dr. Hurtt is interested in the theory and application of community and ecosystem ecology. His primary approach is to combine mathematics and data to develop models for understanding and predicting the structure and dynamics of ecological systems. He has published on a wide range of topics including: the role of dispersal in the dynamics and structure of plant communities, latitudinal and elevational gradients in biodiversity, and ocean and terrestrial ecosystem models for use in studies of the global carbon cycle and global climate change. Current research is focused on the development and application of a new terrestrial ecosystem model that essentially takes a "statistical mechanics" approach to scaling local dynamics to global scales. This model is being used to address issues such as: the sustainability of land-use practices, the potential for terrestrial ecosystems as a carbon sink, and the response and feedback of terrestrial ecosystems to climate and climate change. Dr. Hurtt is involved in several collaborative research projects including the Large Scale Biosphere-Atmosphere Experiment in South America, an Interdisciplinary Science Investigation using NASA's Earth Observing System, and efforts to develop global carbon system and land surface models. He is a coauthor and scientific spokesperson for the New England Regional Assessment of the Potential Consequences of Climate Variability and Change, and has testified to both the New Hampshire Legislature and U.S. Congress on the science of global change. Sonya Legg Sonya Legg received her PhD from Imperial College, London in 1993, and carried out postdoctoral research at the University of Colorado, Boulder, and at UCLA, the latter as a NOAA Climate and Global Change postdoctoral fellow. Prior to arrival in Princeton in September 2004, she worked for seven years as a scientist in the physical oceanography department of the Woods Hole Oceanographic Institution, where she was recently awarded tenure. During her time at WHOI Legg was involved in the MIT-WHOI graduate program, serving on the Joint Committee for Physical Oceanography, and teaching a graduate course in turbulence. Legg is currently an associate member of the IAPSO/SCOR working group 121 on Ocean Mixing, and a member of the US CLIVAR Process Studies and Model Improvement Panel. Legg’s research interests focus on turbulent mixing in the ocean, with primary tools being numerical simulation and theory. Particular processes of current interest include tidal mixing and mixing in overflows. A new emphasis since coming to Princeton is the representation of mixing processes in large scale ocean models such as the GFDL MOM. During the past year Legg has carried out a numerical study of the generation of internal waves and mixing by tidal flow over isolated ridges, such as the Hawaiian Ridge. Of particular interest are the relative proportions of energy entering the wave field and dissipated locally. This study has shown that this ratio depends strongly on the horizontal scale of the topography, with dissipation being most effective for very narrow topography. This work was presented at the Ocean Mixing Symposium in Victoria, Canada, in October 2004, and has been accepted for publication in a special volume of Deep Sea Research. Next Legg intends to incorporate these results into new models of tidal mixing for inclusion in ocean general circulation models. A second major activity of the past year has been the study of overflow mixing processes. Legg is the coordinating PI for a multi-institutional collaboration, the Gravity Current Entrainment Climate Process Team. This CPT brings together observationalists, theoreticians and those carrying out numerical process studies with developers of large scale ocean models such as the GFDL MOM. In addition to being responsible for the organization of the annual workshop in Providence in November 2004, the development and maintenance of the webpage http://www.cpt-gce.org/ , the supervision of a postdoc, Ulrike Riemenschneider, based in Woods Hole, and the preparation of annual reports and numerous presentations, Legg has been active in carrying out several research components of this project. These include a comparison of z-coordinate and isopycnal coordinate representations of overflows with Robert Hallberg (now published in Ocean Modelling) and development of a parameterization of shear-driven mixing in a stratified flow (with Robert Hallberg and Laura Jackson). Hiram Levy, II Dr. Hiram Levy is a Senior Research Scientist and Lecturer in the Department of Geosciences and the Program in Atmospheric and Oceanic Sciences, Princeton University. His current research examines the impact of human activity on the chemistry of the atmosphere and its resulting impact on global air quality, climate, and global biogeochemical cycles. Some specific topics are: The influence of aerosols, both natural and anthropogenic, on air quality and climate; The impact of changing biogenic hydrocarbon emissions on air quality; The interannual variability in CO2 sinks, sources and accumulation; The impact of human fixation of nitrogen on global nitrogen biogeochemistry. Current Research Programs and Collaborations include the following: 1. Biospheric Processes Group [GFDL] - Will work to understand the interactions between the earth's biosphere and climate and assess the impact of human activities. 2. China-MAP [NASA] A measurement and modeling program dedicated to studying the local, regional, and hemispheric impact of pollution emitted from China on both climate and atmospheric chemistry. 3. ITCT [NOAA] and ITCT [Center for Global and Regional Environmental Research/University of Iowa] - A coordinated international research program to investigate intercontinental transport of manmade pollution, with an emphasis on ozone, fine particles, and other chemically active "greenhouse" compounds. Courses taught at Princeton University include: Chemistry of the Environment - CHM333/GEO333; Atmospheric Chemistry and Transport and Atmospheric Chemistry Publications: Fan, S-M., L. W. Horowitz, H. Levy II, and W. J. Moxim, 2004: Impact of air pollution on wet deposition of mineral dust aerosols. Geophysical Research Letters, 31, L02104, doi:10.1029/2003GL018501. Phadnis, M. J., H. Levy II, and W. J. Moxim, 2002: On the evolution of pollution from South and Southeast Asia during the winter-spring monsoon. Journal of Geophysical Research, 107(D24), 4790, doi:10.1029/2002JD002190. Yienger, J. J., M. Galanter, T. A. Holloway, M. J. Phadnis, S. K. Guttikunda, G. R. Carmichael, W. J. Moxim, and H. Levy II, 2000: The episodic nature of air pollution transport from Asia to North America. Journal of Geophysical Research, 105(D22), 26,931-26,945. Denise L. Mauzerall Dr. Denise L. Mauzerall is an Assistant Professor of Public and International Affairs at Princeton University’s Woodrow Wilson School. She completed her undergraduate degree in Chemistry in 1985 at Brown University, a Master’s Degree in Environmental Engineering at Stanford University in 1988, and her Ph.D. in Atmospheric Chemistry at Harvard University in 1996. Previously she was a program manager in the Global Change Division of the U.S. Environmental Protection Agency and a post-doctoral fellow at the National Center for Atmospheric Research. Research in Dr. Mauzerall’s group uses science to contribute to the formation of far-sighted environmental policy. Her research addresses the following central questions: 1) What are present and potential future regional and global levels of air pollution? 2) What are/will be the impacts of air pollution to human health and welfare including climate change? 3) What are appropriate energy and air pollution policy responses? She seeks to answer these questions through research projects on both national and global scales. To address the first question, she uses computer models of regional and global atmospheric chemistry, transport and radiation to simulate the emissions of air pollutants, their chemical transformation and movement around the world. She addresses the second question using tools drawn from agronomy, epidemiology, engineering and economics. Answers to the first two questions facilitate identification of appropriate energy and air pollution policy responses. Her research analyzes the impacts of air pollution in both the largest rapidly industrializing country (China) and in the largest developed country (US). On a global scale she investigates the intercontinental transport of air pollutants with an emphasis on transport from Asia to the US, and the effect of emissions of certain air pollutants (ozone precursors and aerosols) on public health and climate change. Current research includes projects on the impacts of air pollution on agriculture and health in China, intercontinental transport of air pollutants, environmental consequences and alternatives to nitrogen oxide emissions trading, regional attribution of ozone production and associated radiative forcing to emissions from specific regions of the world, and the effect that methane emission controls can have on reducing background ozone concentrations and the associated benefits for human health and climate change. These issues are interlinked, globally pervasive and addressing one provides opportunities for leveraging solutions to others. Identifying policies which can simultaneously reduce the emission of reactive air pollutants and of greenhouse gases are particularly desirable. Michael Oppenheimer Dr. Michael Oppenheimer is the Albert G. Milbank Professor of Geosciences and International Affairs at Princeton University. He is also the Director of the Program in Science, Technology and Environmental Policy (STEP) at the Woodrow Wilson School, and Associated Faculty of the Princeton Environmental Institute and the Atmosphere and Ocean Sciences Program. He joined the Princeton faculty after more than two decades with Environmental Defense. His interests include science and policy of the atmosphere, particularly climate change and its impacts. His research explores the potential effects of global warming, including the effects of warming on ecosystems and on the nitrogen cycle; and on the ice sheets in the context of defining “dangerous anthropogenic interference” with the climate system. He served as a lead author of the Third Assessment Report of the Intergovernmental Panel on Climate Change, and is also a lead author for the Fourth Assessment. He was a member of the National Research Council's Panel on the Atmospheric Effects of Aviation, and currently is a member of the NRC’s panel on "Earth Science and Applications from Space: A Community Assessment and Strategy for the Future". He also has served on several university and institutional advisory boards. Prior to his position at Environmental Defense, Dr. Oppenheimer served as Atomic and Molecular Astrophysicist at the Harvard-Smithsonian Center for Astrophysics and Lecturer on Astronomy at Harvard University. He received an S.B. in chemistry from M.I.T., a Ph.D. in chemical physics from the University of Chicago, and pursued post-doctoral research at the Harvard-Smithsonian Center for Astrophysics. Stephen W. Pacala Dr. Stephen W. Pacala is the Frederick D. Petrie Professor of Ecology and Evolutionary Biology at Princeton University. He completed an undergraduate degree in biology at Dartmouth College in 1978 and a Ph.D. in ecology at Stanford University in 1982. He was Assistant and Associate Professor at the University of Connecticut from 1982 to 1992, and then moved to Princeton University as Professor of Ecology in 1992. He was awarded the Frederick D. Petrie Chair in 2000. He has served on numerous editorial and advisory boards. Dr. Pacala has researched problems in a wide variety of ecological and mathematical topics. These include the maintenance of biodiversity, the mathematics of scaling, ecosystem modeling, ecological statistics, the dynamics of vegetation, animal behavior, the stability of host-parasitoid interactions, the relationship between biodiversity on ecosystem function, and field studies of plants, lizards, birds, fish, insects, and parasites. Since moving to Princeton University, Dr. Pacala has focused on problems of global change with an emphasis on the biological regulation of greenhouse gases and climate. He currently co-directs the Princeton Carbon Mitigation Initiative and directs the Princeton Environmental Institute. S. George H. Philander Dr. George Philander is the Knox Taylor Professor of Geosciences and the Director, Atmospheric and Oceanic Sciences Program at Princeton University. He obtained his Ph.D. at Harvard University in 1970. He studies interactions between the ocean and atmosphere and their role in climate fluctuations and climate changes, in the past and the present. He is particularly interested in El Niño, a phenomenon that brings droughts to the western tropical Pacific, torrential rains to the eastern tropical Pacific, and unusual weather patterns to much of the globe. From an atmospheric point of view, El Niño is attributable to changes in the temperature of the surface waters of the eastern tropical Pacific Ocean sea surface, changes that in turn are caused by altered atmospheric conditions. The ocean-atmosphere interactions implied by this circular argument can also affect global climate changes such as the recurrent ice ages. This possibility is currently being explored by means of a hierarchy of coupled ocean-atmosphere models, from relatively simple analytical models to complex General Circulation Models that require a supercomputer. Philander is a fellow of the National Academy of Sciences, the American Geophysical Union, and the American Meteorological Society. V. Ramaswamy Dr. Ramaswamy is a Senior Scientist at NOAA’s Geosphysical Fluid Dynamic Laboratory. His principal focus of research is the investigation of the climatic effects due to radiatively active gases, aerosols and clouds in the atmosphere. Radiative transfer models of high precision have been developed to determine the forcing exerted by different species upon the surface-atmosphere system. Currently, the perturbations due to changing concentrations of greenhouse gases and aerosols since pre-industrial times are being examined. Numerical models of the atmosphere are used to study the transport and transformation of the species, and to assess their climatic impacts. Another major research aim is to understand the hydrologic cycle in the atmosphere, in particular the processes governing the distribution of water vapor, and the formation, maintenance and dissipation of clouds. The physical properties of aerosols and clouds play a significant role in the radiative balance of the planet, and their accurate evaluation is essential for resolving issues concerning global change. Mathematical models of varying complexity are employed to study different aspects of the global cloud-climate interactions problem. This effort is aided by diagnostic analyses of data drawn from a variety of meteorological and satellite observations. Publications: Erlick, C., and V. Ramaswamy, Note on the definition of clear sky in calculations of shortwave cloud forcing, Journal of Geophysical Research, 108, D5, 4156, doi: 10.1029/2002JD002990, 2003. Garrett, T. J., Lynn Russell, V. Ramaswamy, S. F. Maria, and B. H. Huebert, Microphysical and radiative Evolution of Aerosol Plumes Over the tropical North Atlantic Ocean, Journal of Geophysical Research, 108,4022,DOI: 10.1029/2002JD002228, 2003. Randles, C. A., L. M. Russell, and V. Ramaswamy, Hygroscopic and optical properties of organic sea salt aerosol and consequences for climate forcing, Geophysical Research Letters, 31(L16108), doi:10.1029/2004GL020628, 2004. Ignacio Rodriguez-Iturbe Dr. Ignacio Rodriguez-Iturbe is the Theodora Shelton Pitney Professor in Environmental Sciences and Professor of Civil and Environmental Engineering at Princeton University. He obtained his Ph.D. at Colorado State University in 1967. The dynamics of the interaction between climate, soil, and vegetation are the main focus of Rodriguez-Iturbe’s research group. These dynamics are crucially influenced by the scale at which the phenomena are studied as well as by the type of climate, the physiological characteristics of the vegetation, and the edology of the soil. Moreover, not only the temporal aspects but also the spatial aspects of the dynamics are crucially dependent on the above factors. Soil moisture plays a key role in these dynamics, and his group is involved in its space-time characterization. This involves a range of approaches that include challenging problems in the physics of the interaction as well as on its mathematical description. It is necessary to account for the random character of precipitation, both in occurrence and intensity, as well as for the nonlinear dependence of infiltration, evapotranspiration, and leakage on the soil moisture state. His group’s approach has been to understand and model first the balance of soil moisture at a point under the above conditions. The solution of the stochastic differential equations corresponding to the point dynamics has provided the probabilistic description of the soil-plantclimate interaction at a site. The spatial interaction between different sites with the same or with different types of vegetation is being implemented via cellular automatas operating under rules governed by the characteristics of the stress existing in the vegetation. At larger spatial scales, precipitation itself is influenced by the soil moisture present in the region, and this phenomenon needs to be incorporated into the modeling scheme. At intermediate scales involving river basins, the geomorphologic characteristics of the drainage network is a commanding factor in the spatial organization of soil moisture. Rodriguez Iturbe’s group is trying to link the recent advances on the scaling characteristics of the network with the dynamics of the soil moisture. With the above framework the group hopes to elucidate some of the most fundamental issues of the climate-soil-atmosphere interaction that lie at the heart of hydrology. Rodriguez-Iturbe was awarded the Stockholm Water Prize in 2002. Jorge L. Sarmiento Dr. Jorge L. Sarmiento is a Professor of Geosciences at Princeton University. He obtained his Ph.D. at the Lamont-Doherty Geological Observatory of Columbia University in 1978, and then served as a postdoc at the Geophysical Fluid Dynamics Laboratory/NOAA in Princeton before joining the Princeton University faculty in 1980. He has published widely on the oceanic cycles of climatically important chemicals such as carbon dioxide, on the use of chemical tracers to study ocean circulation, and on the impact of climate change on ocean biogeochemistry. He has participated in the scientific planning and execution of many of the largescale multi-institutional and international oceanographic biogeochemical and tracer programs of the last two decades. He was Director of Princeton's Atmospheric and Oceanic Sciences Program from 1980 to 1990, and is presently Director of the newly formed Cooperative Institute for Climate Science. He has served on the editorial board of multiple journals and as editor of Global Biogeochemical Cycles. He is a Fellow of the American Geophysical Union and the American Association for the Advancement of Science. Daniel M. Sigman Dr. Daniel M. Sigman is an Assistant Professor of Geosciences at Princeton University. He obtained his Ph.D. at Massachusetts Institute of Technology and Woods Hole Oceanographic Institution in 1997. He studies the cycles of biologically important elements and their interaction with changing environmental conditions through the course of Earth history. His current research activities include the development of stable isotope methods by which to track the marine nitrogen cycle, today and in the past, and the construction of simple geochemical models for paleoceanographic and Earth history studies. Much of his work to date has focused on the oscillation between ice ages and interglacial periods that has dominated Earth’s climate for the last two million years. These cyclic climatic changes provide an important test case for the interaction between physical and biological processes in setting environmental conditions on Earth. Ongoing studies of the nitrogen cycle in the modern ocean use the isotopic composition of dissolved nitrogen species to understand the internal cycles and input/output budgets of nitrogen and other biologically important elements in the ocean. Sigman’s studies of the history of the nitrogen cycle make use of the organic matter preserved within microfossils as a recorder of nutrient dynamics in the surface ocean, with the goal of understanding the relationship between nutrient supply and algal growth, which may be an important driver of past changes in the atmospheric concentration of carbon dioxide. Through the work of his students and collaborators at Princeton, Sigman has also begun to explore the atmospheric reactive nitrogen cycle and the nitrogen budgets of terrestrial ecosystems, both their modern conditions and their changes through time. Eli Tziperman Dr. Eli Tziperman obtained a B.A. in Physics and Mathematics from Hebrew University in Jerusalem (1982), Ph.D. in Physical Oceanography from the joint program in Oceanography of MIT and WHOI (1987). He was at the Weizmann Institute of Science until 2003, and has been in the Department of Earth and Planetary Sciences and the Division of Engineering and Applied Sciences at Harvard University since. Over the past 15 years, he spent two full-year sabbaticals and some 12 two-month summers at GFDL/ Princeton University. His interests include large scale ocean and climate dynamics, from El Nino’s dynamics, to that of the thermohaline circulation, Heinrich events and glacial cycles. In addition, a more applied side to his work involves the development of four dimensional data assimilation methods based on the adjoint method, in order to try and improve the prediction skill of El Nino/ La Nina events. The support from GFDL/Princeton/ Cooperative Institute for Climate Science (CICS) allowed making significant progress toward completing an adjoint to the latest GFDL ocean model. This adjoint will be used for sensitivity studies, data assimilation, and ENSO prediction. The post doc working on this project, Geoffrey Gebbie, has previously completed his PhD at MIT. Geoffrey Vallis Dr. Geoffrey Vallis has been at Princeton since 1998. Prior to that, he was a Professor at the University of California. He works in a variety of topics in large-scale dynamics in the ocean and atmosphere. Recent research topics include: Investigations of the dynamics of the North Atlantic Oscillation and so-called annular modes of variability. Vallis, in collaboration with colleagues and students, has shown how the NAO and annular modes are two sides of the same coin, and how variations in the Atlantic storm track are intimately tied to the NAO. Investigations of mesoscale eddy effects in the ocean. With a Princeton graduate student, Vallis has shown how and why the mesoscale eddies have a leading order affect on the Antarctic Circumpolar Current. Investigations of the nature of climate variability on millennial timescales. In collaboration with a graduate student, Vallis has suggested that a natural instability of the overturning circulation of the ocean might give rise to Dansgaard-Oeschger oscillations, and explain the nature of climate variability in glacial climates. From 1998-2004 he was editor of Journal of Atmospheric Sciences. He has recently completed a book, Atmospheric and Oceanic Fluid Dynamics, to be published by Cambridge University Press. Charles J. Vörösmarty Dr. Charles J. Vörösmarty is a Research Professor in Biogeochemical Modeling at the University of New Hampshire. His research interests are focused on the interaction between hydrology, water resources, and biogeochemistry, and he has been active in the field for nearly twenty years. His research has included studies at local, regional, and global scales, including development of nutrient cycling models in New England coastal ecosystems; continental to global-scale modeling of water balance, discharge, sediment and nutrient delivery in the world's large river systems; and the influences of large-scale water engineering on continental runoff. Dr. Vörösmarty 's publications have appeared in Science, AMBIO, Climatic Change, Ecological Applications, Estuaries, Global Biogeochemical Cycles, Nature, Studies in Geophysics, Journal of Hydrology, and Water Resources Research. His research has relied on geographically-specific data sets and models. He and his co-workers have developed the Global Hydrological Archive and Analysis System (GHAAS), an interactive data base and scientific visualization package used in analyzing water and biogeochemical cycles at a variety of spatial scales. Applications of the GHAAS have included: orbital analysis of alternative remote sensing systems for inland water monitoring, indicators of water resource scarcity, the linking of remote sensing, groundbased meteorological data, and drainage basin models to monitor river discharge; geographically-specific analysis of the impact of large reservoirs on drainage basin response; development of high resolution runoff fields from the blending of modelled discharge, observed station data and river networks at the global scale. Dr. Vörösmarty has been active in numerous international committees including the International Geosphere-Biosphere Programme (IGBP) Biospheric Aspects of the Hydrological Cycle and UNESCO's International Hydrological Programme. He serves as co-chair of ESSP Global Water System Project. Vörösmarty is a Coordinating Level Author on the freshwater chapter of the Millennium Assessment. He also serves as President of the International Committee on Atmosphere-Soil-Vegetation Relations of the International Association of Hydrological Sciences. Main support for his work has come from NASA, the U.S. Environmental Protection Agency, the Department of Energy, and the National Science Foundation. Eric F. Wood Dr. Eric F. Wood is Professor of Civil and Environmental Engineering at Princeton University and an associated faculty member in the Geosciences Department and the Princeton Environmental Institute. After receiving his doctoral degree in Civil Engineering from the Massachusetts Institute of Technology in 1974, he spent 2 ½ years at the International Institute of Applied System Analysis in Laxenburg Austria conducting research into water resources and statistical hydrology. He joined Princeton University as an Assistant Professor in the fall of 1976. He has held a number of administrative positions while at Princeton including acting departmental chair in 1986-1987, Director of the interdepartmental Program in Environmental Engineering and Water Resources from 1980 to 1994, and departmental Director of Graduate Studies from 1994 to 1997 and currently since July 2005. He has also sat on a number of university committees, including two terms on the Priority Committee. Dr. Wood is a Fellow of the American Geophysical Union (AGU) and of the American Meteorological Society. He has received the AGU's Robert E. Horton Award, AMS's Robert E. Horton Memorial Lectureship and Princeton's Rheinstein Award. His current research areas include hydroclimatology with an emphasis on land-atmospheric interaction and the development and validation of large scale terrestrial hydrologic models; hydrological remote sensing, including the retrievals of soil moisture and evaporation using NASA Earth Observation satellites; the modeling and analysis of the terrestrial water and energy budgets over a range of scales, including seasonal climate forecasting and hydrologic prediction studies; and hydrologic impact of climate change. In the area of remote sensing, he is a Science Team member on the NASA Aqua/Terra AMSR-E and MODIS instruments, and on the proposed HYDROS soil moisture/freeze-thaw mission. He also serves on a bilateral NASA/NASDA science steering group for the Global Precipitation Mission (GPM). As part of his remote sensing science research, he and his research team has helped plan and have participated in numerous field campaigns over the last 20 years, including Italy, Arizona, Oklahoma and Iowa. Also, he is developing forward radiative transfer models of terrestrial surface emission for the NOAA Joint Center for Satellite Data Assimilation. In the area of hydrological modeling, he and colleagues at the University of Washington have over the last decade developed one of the most widely used and cited macro-scale land surface models appropriate for climate modeling and global-scale offline simulations. The model also forms the core of the NOAAsupported seasonal hydrologic forecast system that ingests NCEP seasonal climate predictions and produces seasonal hydrologic predictions, and a U.S. drought nowcast useful to the NOAA Climate Prediction Center’s drought assessment activities. Professor Wood has performed extensive professional service to his community, including being a Council member of the American Meteorological Society (1999-2002), where he currently serves on their Atmospheric Awards Committee (2003-2005). For the American Geophysical Union, he has served on numerous committees, including as a member and chair of the Union Fellows Committee and on the executive of the Hydrology Section. For the World Climate Research Programme, he served on the Task Force that just completed the strategic plan for the new Coordinated Observations and Predictions of the Earth System (COPES) and is co-chair of the Science Advisory Group for the U.S. GEWEX Americas Prediction Project (GAPP). For the National Research Council he has served on the Water Science and Technology Board (1997-2000) and the Board on Atmospheric Science and Climate (1999-2002), as well as numerous study and standing committees. Currently he is a member of the joint WSTB/BASC standing Committee on Hydrological Sciences, where he serves as its Chair, and is vice-chair of the current study Committee on Integrated Observations for Hydrologic and Related Sciences. Research Staff, Scholars, Professional Technical Staff and Postdoctoral Fellow Bios Alistair Adcroft, Research Oceanographer Alistair Adcroft received his PhD from Imperial College, London in 1995, and carried out postdoctoral research at the University of California, Los Angeles, as a UCAR Ocean Modeling postdoctoral fellow and then at MIT, Cambridge, in the Program in Atmospheres, Oceans and Climate. He worked at MIT for seven years, first as a research fellow, then as a research scientist and finally as a principle research scientist, during which he led the development of the MIT general circulation model. During this time, he was involved in various working groups such as the U.S. Climate modeling infrastructure, that led to the creation of the ESMF project; and the ONR Terrain-coordinate Ocean Modeling Systems “Expert group”. He has also organized workshops and sessions including the “Z-coordinate ocean modeling meeting” and the “Future directions” session for CLIVAR ocean modeling workshop. Adcroft was appointed as a research oceanographer at Princeton University in September, 2004. Adcroft’s research interests focus on the improvement of models both for climate research and for process studies. A particular underlying theme involves building robust tools that can seamlessly simulate the wide range of scales seen in the ocean. During the past year Adcroft has been working on the foundations of a new kind of ocean model. The foundations include improved infrastructure capabilities (such as novel grids, nesting, object oriented components). More recently, he has begun work on the building blocks for the new ocean model, known as kernels, which embody the shared part of several different ocean models. The kernels will be usable by existing models and will be the principal components of a new model developed with hybrid vertical coordinates in mind. The objective is to both unify our current capabilities into one modeling framework and at the same time to extend our capabilities into a promising research area. The kernels and overall strategy are being described by white papers which will be sent out to the community for comment: the expectation being that certain members of the community will want to buy-in to the new software as it becomes available. Adcroft has also been working on fine tuning a high-resolution regional model of the Irminger Sea (in collaboration with Tom Haine, Johns Hopkins Univ.); improving the representation of grid-scale topography (thin-walls and porous barriers); developing a framework for sub-grid scale eddy closures which provides the eddy velocity scale to the parameterizations and at the same time makes the model energetically closed; developing time-stepping methods for the primitive equations that reduces the size of the state vector; developing vorticity advection schemes that avoid the need for artificially large viscosities in ocean models. Andrew S. Altevogt, Research Staff Department of Civil and Environmental Engineering Princeton University Andrew Altevogt received his Ph.D. in Hydrologic Sciences from the University of California, Davis in 2001. His dissertation was entitled A Determination of the Flux of Gas Phase Volatile Organic Compounds Due to Naturally Occurring Environmentally Significant Driving Forces. His research interests include: Fate and transport of chemicals in porous media, environmental fluid mechanics, and scale dependent processes. Recent research projects include modeling the biogeochemical effects of CO2 leakage from areas of geological sequestration and mathematical and experimental determination of the theoretical relationships between transport and chemical reaction in porous media. Currently he is implementing a coupled multi-phase reactive transport model which will describe the emission of nitrogen compounds during periods of changing soil moisture. The information gained from this modeling effort will be utilized to examine the temporal and spatial scale dependencies of nitrogen transformation in soils as zones of anoxia form and then disappear as a result of soil wetting and drying. Capturing the details of these dynamic processes will enhance the predictive capabilities of future regional and global scale modeling efforts. Selected Publications: Altevogt, A. S. and P. R. Jaffe. “ Biogeochemical Response of Unsaturated Soils to CO2 Intrusion.” Water Resources Research.. 41:9, W09427. (2005) Altevogt, A. S. and M. A. Celia. “Numerical Modeling of Carbon Dioxide in Unsaturated Soils due to Deep Subsurface Leakage”. Water Resources Research. 40:W03509. doi:10.1029/2003WR002848 (2004). Altevogt, A. S., D. E. Rolston and S. Whitaker. “New Equations for Binary Gas Transport in Porous Media, Part 1: Equation Development”. Advances in Water Resources. 26:7. pp 695-715. (2003) Altevogt, A. S., D. E. Rolston and S. Whitaker. “New Equations for Binary Gas Transport in Porous Media, Part 2: Experimental Validation”. Advances in Water Resources. 26:7. pp 717-723. (2003) Venkatramani Balaji, Prof. Technical Staff V. Balaji serves as Head, Modeling Systems Group at the Cooperative Institute of Climate Sciences of Princeton University. Balaji’s background is in the modeling of cloudscale dynamics (nonhydrostatic moist convection and gravity waves) and its effect on climate. This field has always involved the application of the most advanced computational technologies to science, and the development of interdisciplinary models requiring specialists in many fields (meteorology at various scales, hydrology, radiative transfer, and boundary layer dynamics). His publications cover the breadth of the field: they include papers on atmospheric climate, ocean dynamics, cloudscale dynamics, non-hydrostatic models of gravity waves, computational methods, and software engineering. Over the years, this breadth has evolved into an interest in the development of modeling infrastructures, beginning with the creation of the GFDL Flexible Modeling System, of which he is the chief architect, moving to technical leadership roles in international consortia to build similar frameworks across multiple institutions (the Earth System Modeling Framework in the US, and the Program for Integrated Earth System Modeling in Europe). Several key interdisciplinary consortia centered on the University (the Carbon Modeling Consortium, the Carbon Mitigation Initiative) are already built upon FMS-based modeling technologies developed under Balaji’s guidance. These technologies aid the progress of Princeton research teams dispersed among multiple investigators, in the building of complex coupled models to study ocean biogeochemistry, land biosphere dynamics, hydrology, and other climate change impacts. The FMS has evolved into a unique tool for constructing these complex models: nowhere else are these technologies available for immediate deployment. Balaji is currently a principal investigator on an NSF SEIII grant to build a prototype environment called the Earth System Curator. The Curator begins with the insight that a scientifically comprehensive description of a model output dataset is the model configuration itself. By expressing this in a common language, it is possible for either an exact model configuration, or a dataset from an existing model run, to be the result of a scientific query. The Curator’s foundation is a database from which it is possible to extract on the basis of such queries, either a model or an archived dataset for a particular experiment. Balaji is also a principal investigator on the NASA-funded proposal MAPS to assemble standard coupled climate model out of a range of ESMF-enabled model components. Marcelo Barreiro, Research Associate I completed my PhD in Physical Oceanography at Texas A&M University in August 2003. In January 2004 I moved to Princeton University, where I started working with Professor George Philander (Princeton Univ.) and Ronald Pacanowski (GFDL). My research aims to understand the evolution of the tropical oceanatmosphere state, and its role in the present and past climates. Recent paleo-data suggests that the current mean state of the tropical oceans with a cold tongue in the east and a warm pool in the west may have been different 5 to 3 million years ago. These data indicate that during the early-middle Pliocene the eastern sides of the tropical oceans were as warm as the western sides and coastal upwelling regions did not exist. Interestingly, the Pliocene was also the last period when the global climate was significantly warmer than the present, even though the main external factors that determine climate -global geography and the concentration of greenhouse gases- were essentially what they are today. Using atmospheric general circulation models we have shown that a state of uniform tropical sea surface temperature warms the climate by increasing the amount of atmospheric water vapor and decreasing the albedo of the Earth, thus providing a new mechanism that could have contributed significantly to Pliocene warmth. I am now investigating how this state of uniform tropical conditions can be induced and maintained. A recent study with simple ocean models proposed that the degree of tropical east-west asymmetry can be varied by changing the oceanic heat loss in high latitudes. Currently, the oceans gain heat in the equatorial regions where cold waters upwell, and lose heat in high latitudes. Thus, were the oceans to lose less heat in high latitudes, the need to maintain a balanced heat budget would require the ocean to gain less heat, reducing the eastern cold tongue. I am currently studying if this mechanism can induce a state of uniform tropical conditions. Initial results are encouraging, and show that a freshening of surface waters in the North Pacific can induce such a state in a coupled ocean-atmosphere model. These experiments may not only provide clues to understand the early Pliocene climate, but also demonstrate another way of rapid climate change since the adjustment of the upper ocean occurs in the order of decades. Cyril Crevoisier, Research Associate After studying at the Ecole Normale Supérieure de Cachan in France, I have obtained my PhD in remote sensing from the University of Paris VII in October 2004. My thesis dealt with the estimation of atmospheric CO2 distribution from space observations, using highspectral resolution infrared instruments. Three papers have been published on this topic. In November 2004, I joined the Program in Atmospheric and Oceanic Sciences at Princeton University. My research projects deal with getting a better understanding of carbon surface fluxes, with a focus on North America. First, to exploit the measurements of CO2 vertical profiles by aircraft and tall towers, that will soon be available at twenty locations across North America, in the framework of the North American Carbon Program (NACP), I have developed a direct carbon budgeting approach. Direct budgeting puts a control volume on top of North America, balances air mass in- and outflows into the control volume and solves for the surface fluxes. This method has been tested with CO2 simulations combining an atmospheric transport model, a land ecosystem model and an oceanic model. It has been used to test the planned observation network and propose alternative sites. This work has been presented at the Seventh International Carbon Dioxide Conference in October 2005 and a paper is about to be submitted to Tellus. Secondly, I am developing a fire model for boreal forests to reinforce the land ecosystem model LM3, which is developed at GFDL. Indeed, understanding the role of boreal forests in the global carbon cycle is needed to accurately simulate the future behavior of these pools of carbon in the context of global warming, and fires represent a major factor that influences the structure and carbon dynamics of the boreal forest. An ignition function combining thermodynamic and human-related variables is being tested against observations. A paper should soon be submitted. These studies rely on simulations of atmospheric transport (MOZART model), air-land fluxes (LM3 ecosystem model) and oceanic air-sea fluxes (from the new GFDL model designed by John Dunne). These models have been designed at Princeton University and GFDL and I am taking part in their evaluation against in-situ observations of CO2 and O2 atmospheric concentrations. I am also part of a project that will soon be submitted to NASA, dealing with the use of satellite observations in conjunction with an oceanic and an atmospheric transport models to improve CO2 flux estimates over North-America. Agatha M. de Boer, Research Associate Agatha de Boer completed her Ph.D. in physical oceanography at Florida State University in January 2003. She started a visiting scientist research position in the AOSP/CICS program in March of that year. Since arriving at Princeton, she has published 3 first author papers and 1 second author paper related to her dissertation work. Agatha’s primary research interest is the interaction of the large scale ocean circulation with climate, now and in the past. Her initial projects at Princeton were with Robert Toggweiler and Daniel Sigman. The first of these was to determine whether the observed link between ocean temperature and deep ventilation in the paleorecord could be explained by the fact that the sensitivity of density to temperature is higher in warm climates, thereby increasing the thermal forcing in the ocean. The second project aimed to understand the role of winds on the ocean circulation, as a provider of energy, as a dynamic constraint, and through its effect on the thermodynamics. The above questions were addressed with the help of GFDL’s ocean model, MOM4, coupled to a sea-ice model and energy balance model for the atmosphere. With this work underway, Agatha started a collaborative project with Bill Hurlin to test one of the hypotheses of her Ph.D. dissertation, i.e., that the opening of the Bering Strait 10,000 years ago lead to the stabilization of the thermohaline circulation and thus explains the relatively stable climate of the Holocene. As set of experiments were carried out in a high resolution, realistic topography version of the MOM4 models used in the previously mentioned process-orientated studies. More recently, Agatha is involved in a study with Anand Gnanadesikan to asses the applicability to the real ocean of the often used proportionality of the meridional density gradient to the overturning circulation. Of the above projects, 1 paper has been submitted and 3 are pending. Papers published and submitted while working at Princeton in the CICS/AOS program: De Boer, A. M and D. Nof, 2004, The exhaust valve of the North Atlantic. Letter in J. Climate, 17, 417-422 Nof, D. and A. M. de Boer, 2004, From the Southern Ocean to the North Atlantic in the Ekman layer? Bull. Amer. Meteor. Soc. 85, 79-87 De Boer, A. M and D. Nof, 2004, The Bering Strait 's Grip on the Northern Hemisphere Climate. Deep-Sea Res., 51, 1347-1366 De Boer, A. M and D. Nof, 2005, The Island Wind-Buoyancy Connection. Tellus, 57A, Issue 5, 783797 De Boer, A. M, D. M. Sigman and J. R. Toggweiler, 2005, The effect of global ocean temperature change on deep ocean ventilation. Paleoceanography, submitted. Simon Donner, Research Associate Simon Donner completed his PhD in Atmosphere and Ocean Sciences at the University of Wisconsin-Madison at the end of 2002. He began working with Michael Oppenheimer at the Woodrow Wilson School of Public and International Affairs in early 2003. His research has focused on climate variability, large scale nutrient cycling and the health of aquatic ecosystems. Over the past two years, he has refined hydrology and nutrient cycling models developed during his PhD work to examine the impact of climate variability and land use policy decisions on the flux of nitrogen by Mississippi River the Gulf of Mexico. One study found that the removal of nitrogen via in-stream processes like denitrification and the associated N2O emissions can vary two- to three-fold annually due to variability in rainfall. A second found that shifting from animal feed to direct human food cultivation in the central U.S. could reduce the nitrate flux by the Mississippi River by over 40% and meet the EPA goal of reducing the seasonal hypoxic zone in the Gulf of Mexico to less than 5000 km2. Ongoing research is looking at how variability in precipitation [and climate indices] can be used to predict nitrate export by large rivers and coastal health. The rest of Donner’s time has been spent examining the possible impacts of climate variability and climate change on the frequency of coral bleaching. A global study conducted in collaboration with the NOAA Coral Reef Watch Program found that the majority of the world’s coral reefs will experience annual or bi-annual bleaching within the next 30-50 years without an increase in their thermal tolerance by 0.2 – 1.0 °C. The research is focusing specifically on the central Pacific (e.g. Republic of Kiribati) where corals reefs are expected to be particularly vulnerable to variable ocean conditions and future climate change. Publications: Donner, S,D. Surf or turf? Shifting from feed to food cultivation could reduce nutrient flux to the Gulf of Mexico. Submitted to Global Environmental Change. Boyer, E.W, Alexander, R.B., Parton, W.J., Li, C.S., Butterbach-Bahl, K., Donner, S.D. and Skaggs, R.W. Modeling denitrification in terrestrial and aquatic ecosystems at regional scales: current approaches and needs. Submitted to Ecological Applications. Donner, S.D., Skirving, W.J., Little, C.M., Hoegh-Guldberg, O and Oppenheimer, M. Global assessment of coral bleaching and required rates of adaptation under climate change. Global Change Biology, in press. Donner, S.D., Kucharik, C.J. and Oppenheimer, M. (2004) The influence of climate on in-stream removal of nitrogen. Geophysical Research Letters, 31, L20509. Editor’s Choice in Science, November 19, 2004. Stefan Gerber, Research Associate Stefan Gerber completed his PhD Thesis at the University of Bern, Switzerland in December, 2003. He started his postdoctoral work at Woodrow Wilson School and the Department of Ecology and Evolutionary Biology in July 2004, with Professor Michael Oppenheimer and Professor Lars Hedin. His research focuses on the implementation of a global model of a terrestrial nitrogen cycle within the framework of the existing Earth System Model at the Geophysical Fluid Dynamic Laboratory. Recently, an early version of a nitrogen model has recently been put in place. It has a fixed carbon/nitrogen stoichiometry in plants and in soil organic matter, which allows for nitrogen imitation in plant uptake and litter decomposition, while excess nitrogen is leaching as a function of water export. Today, the application of fertilizers and anthropogenic emissions of reactive nitrogen greatly exceed pre-industrial bio-available nitrogen deposition into terrestrial systems. While some of this nitrogen can be absorbed in vegetation and soils, the remainder cascades through rivers, lakes, and estuaries, greatly disturbing these systems. On the other hand, terrestrial sequestration of anthropogenic emissions of carbon dioxide also depends on the supply of nitrogen. A coupled model of the terrestrial carbon and nitrogen cycles is therefore an important tool to account for feedbacks in terrestrial carbon and nutrient cycle, and provides useful insights in the response of the global biogeochemical cycles to changes caused by human activity. Manuel Gloor, Research Scholar Manuel Gloor studied physics at and has a PhD from ETH, Zurich, Switzerland and is currently senior scientist at Princeton University. During his PhD he developed and applied temperature microstructure and tracer techniques to study dispersion of tracers in lakes. He was a Post-Doc at Princeton University in the Programs of Atmospheric Sciences and Ecology and Evolutionary Biology. His post doctoral work focused on data analyses and inverse modelling of the carbon and oxygen cycles in the atmosphere and the oceans. He then held a post as senior scientist at the max-Planck Institute for Biogeochemistry in Jena, Germany where he helped initiate tall tower greenhouse gas measurement programs across Eurasia. A focus of his current work is modelling of the carbon cycle on continents on regional and global scales to assist the interpretation of carbon measurements on land with the ultimate aim to improve our understanding of the interactions between the biosphere and climate. Xianglei Huang, Research Associate Xianglei Huang received his Ph.D. from California Institute of Technology in June 2004. He joined AOS program at Princeton University as a postdoctoral research associate in the same month. He has been working on understanding the variability of the thermal IR radiances and exploring efficient ways to use such observations to evaluate the performance of the new GFDL AGCM, AM2. Huang studies the temporal and spatial variability seen from outgoing thermal IR radiances and then examines how good such variability could be represented in current GCMs. With a careful treatment of the sampling disparity between GCM and satellite observations, Huang has applied the “model-to-satellite” approach to evaluate model performance with respect to satellite observations of IR radiances. This approach computes synthetic IR spectra and narrowband radiances based on GCM outputs and then directly compares these synthetic quantities with observed ones. This approach is affordable with today’s computational power and effectively avoids the uncertainty resulted from ill-posed nature of IR retrieval. Three subtasks have been carried out in since Huang’s arrival at Princeton University: (1) Temporal and spatial variability of observed and simulated IR spectra; (2) Interannual co-variability seen from comparisons among HIRS observation, AM2 simulation and reanalysis; (3) Quantify the source of errors in AM2 simulated tropical clear-sky OLR; (4) the influence of ozone change on recent cooling of tropical lower stratosphere. The results from subtask (1) and (2) were published on peer-reviewed journals. The subtask (3) was also finished and the manuscript based on it is currently under peer review. The subtask (4) is still an ongoing project and preliminary result will be presented in the incoming 2005 Fall AGU conference. Besides these activities, Huang has been a collaborator in two projects lead by J. Anderson and B. Farrell at Harvard University, exploring the linear stochastic representation of variability seen in infrared spectra. He has also co-authored three papers, ranging from the fast radiative transfer, variability in earth upper troposphere, to the interaction between zonal flow and moist convections in Jovian atmosphere. Publications: Huang, X.L., and Y. L. Yung (2005), Spatial and spectral variability of the outgoing thermal IR spectra from AIRS: A case study of July 2003, Journal of Geophysical Research - Atmospheres, 110, D12102, doi:10.1029/2004JD005530. Huang, X.L., B.J. Soden, and D.L. Jackson, Interannual co-variability of tropical temperature and humidity: a comparison of model, reanalysis data and satellite observation, Geophysical Research Letters, 32, L17808, doi:10.1029/2005GL023375, 2005. Soden, B.J., D.L. Jackson, V. Ramaswamy, M.D. Schwazrzkopf and X.L. Huang, The radiative signature of upper tropospheric moistening, Science, 10.1126/science.1115602, 2005.. Natraj, V., X. Jiang, R.-L. Shia, X.L. Huang, J.S. Margolis, and Y.L. Yung, The Application of Principal Component Analysis in Fast, Highly Accurate and High Spectral Resolution Radiative Transfer Modeling: A Case Study of the O2 A-band, Journal of Quantitative Spectroscopy and Radiative Transfer, 95(4), pp. 539-556, November 2005. Li, L., A.P. Ingersoll, X.L. Huang, Interaction of Moist Convection with Zonal Jets on Jupiter and Saturn, Icarus, in press. Submitted: Huang, X.L., V. Ramaswamy and M. D. Schwarzkopf, Quantification of the source of errors in AM2 simulated tropical clear-sky OLR, submitted to Journal of Geophysical Research – Atmospheres Laura Jackson, Research Associate I arrived at Princeton University in August 2004 having completed my PhD in Physical Oceanography at Liverpool University, UK. Since then I have written and had accepted a paper based on my PhD work (see below). At Princeton I have been working in the joint Atmospheric and Oceanic Sciences program with Princeton University and the Geophysical Fluid Dynamics Laboratory (NOAA). I am involved in two projects: the Gravity Current Entrainment climate process team and Eddy Mixed Layer Interactions climate process team, although my work to date has mainly been on the former. This past year, I have been working on documenting the sensitivity of overflows to the range of parameters of our existing shear-mixing scheme; developing a new entrainment and shear-driven diapycnal mixing parameterization; and implementing this new parameterization for use in our climate models. To develop this new parameterization I have been running Large Eddy Simulations of shear-driven, stratified, turbulent mixing. We will compare these results with both gravity current simulations from our collaborators in Miami, and also with new and existing theories for gravity current entrainment. In addition, as part of the other CPT project I will be a part of the effort at GFDL to implement and evaluate the eddy-driven mixed layer restratification parameterizations now under development at MIT. Publications: Jackson, L., R. G. Williams, and C. W. Hughes, 2005: Topographic control of basins and channel flows: the role of bottom pressure torques and friction. J. Phys. Oceanogr., accepted Andrew Jacobson, Research Staff Andy Jacobson earned undergraduate degrees in physics and psychology at the University of Illinois in 1989. He then joined the Peace Corps and left for Bénin, West Africa, where he taught secondary school science. Thereafter he worked on famine early warning systems for the U.S. Geological Survey and the World Meteorological Organization in Niamey, Niger, for three years. He earned a doctorate in meteorology at Penn State University in 2001, for which he used techniques of acoustic tomography to study the temperature structure of the North Pacific Ocean. Jacobson has interests in applying mathematical and statistical techniques to understanding observations of natural systems. Recently he has been studying how ocean and atmospheric CO2 measurements can be interpreted in terms of surface fluxes. In this work, observed spatial and temporal variations of CO2 concentrations are interpreted as fluid transport in the atmosphere and ocean acting on terrestrial and oceanic sources and sinks. Other interests include development of conceptual models of ecosystem structure in the ocean based on satellite observations of ocean color. Xianan Jiang, Research Associate Xianan Jiang received his Ph.D. from the University of Hawaii at Manoa in May, 2004, where he studied the dynamical mechanisms for the tropical intraseasonal oscillation. In October 2004, he arrived at Princeton University as a visiting scientist working with Drs. NgarCheung Lau and Isaac Held at GFDL. His study at Princeton is mainly dedicated to a better understanding of the warm season climate regime over the U.S. region and improvement of the GFDL AGCM in simulating this regional climate system. Since his arrival, Xianan Jiang has placed his main efforts on two specific topics. The first one is on the mechanisms of the formation of Great Plains Low-Level Jet (GPLLJ), which is one of the key components of summertime climate system over North America. Based on successful simulation of the GPLLJ by the GFDL AGCM, the physical mechanisms for the formation of this nocturnal low-level jet are re-evaluated in the context of existing theories. A simple model has also been developed to serve this purpose. The results illustrate that both of the two mechanisms, i.e., alternative heating and cooling of sloping terrain and the inertial oscillation due to frictional decoupling, play essential roles in shaping the observed GPLLJ. This part of work has been organized, and is to be submitted for publication shortly. Meanwhile, Xianan Jiang has been investigating the mechanisms for the diurnal cycle of summertime rainfall over the U.S. Great Plains. The simulation of diurnal cycle of rainfall over this region remains a great challenge for most of current AGCMs, including the GFDL AGCM. The AGCM simulated rainfall tends to have an afternoon peak instead of a nocturnal one as in the observations. Currently, on one hand, Xianan Jiang is diagnosing the observed data in order to identify the key factors responsible for the precipitation regime in the real atmosphere; on the other hand, he is performing detailed comparison between the AGCM simulation and its observed counterpart, so as to obtain some clues for improving the model performance. Publications: Xianan Jiang, Ngar-Cheung Lau and Isaac. M. Held: AGCM simulated Great Plains Low-level Jet and its Mechanisms. To be submitted. Robert M. Key, Research Oceanographer My research interests are rather eclectic, however a common thread is the application of chemical tracers to the study large scale oceanic processes. The scale of these projects is such that the majority of my work tends to be highly collaborative. Recent projects include investigation of the global radiocarbon distribution, deriving a method to separate bomb-produces and naturally occurring radiocarbon, using the bomb-radiocarbon inventory to derive an improved estimate of the air-sea gas exchange rate, estimating the global inventory of anthropogenic carbon dioxide and investigating the flux of carbon dioxide between the atmosphere and ocean, using various tracer distributions to constrain and improve numerical ocean circulation models, quantification of the volume, distribution and mixing of the primary oceanic water masses, determination of the Redfield ratio variation in the ocean , various studies of major nutrient cycling and investigating the influence of bottom topography of advection and diffusion in an isopycnal coordinate ocean model. By necessity, I have done a significant amount of fieldwork, including approximately 3 years at sea on various oceanographic cruises, helping to generate the required volume of data. During the 1990s I led the radiocarbon program for the World Ocean Circulation Experiment as well as participating in the U.S. carbon effort for WOCE and JGOFS. Prior to that, the focus was on uranium-thorium series isotope measurements. Since the end of the major global expeditions in 1998, I have focused that time on assembling those data required to study biogeochemical process into an easily usable, uniform high quality database. The first version of this database was released for public use in 2004 as GLODAPv1.1 and distributed through the Carbon Dioxide Information Analysis Center (CDIAC). This database and the products derived from it provided the first three dimensional global description of the distribution and inventory of numerous chemical tracers including dissolved inorganic carbon, alkalinity, chlorofluorocarbons, and radiocarbon. This work continues and future versions will include additional tracers as well as more data. Lifeng Luo, Research Staff Lifeng Luo received his Ph.D. in Environmental Sciences from Rutgers University in May 2003 and started working at Princeton University as a postdoctoral researcher with Prof. Eric F. Wood in the Department of Civil and Environmental Engineering. He is generally interested in prediction of the hydrological variables at seasonal timescale. A fundamental challenge for seasonal forecasting, in particular forecasting of hydrological extremes (drought and flood), is to determine the extent to which climate can be predicted on timescales of weeks to seasons, and to provide such forecasts, and their quantified uncertainties that are useful to decision making. One focus of his research is to study the predictability of the climate system at seasonal timescale through modeling studies with general circulation models (GCMs) as they provide a useful means to understand the natural variability and predictability of the real world. Another focus of his research is to make useful hydrological predictions using current available tools. He has built a seasonal hydrological forecast system that takes in seasonal forecasts from climate models such as the NCEP Climate Forecast System (CFS), and produces a posterior forecast at suitable spatial scales through a Bayesian merging method. Such a posterior forecast is then used to drive the VIC hydrological models to make an ensemble forecast of surface hydrological variables such as streamflow and soil moisture. This system has been applied over the Eastern US and produced near real-time forecast on a monthly basis. Hindcasts with this system have shown skills and demonstrated the usefulness of such forecast. Lifeng is currently preparing several papers that document his research in the last two years with two of them on seasonal predictability, one on seasonal hydrological prediction and one on hydrological impact of climate change over the Northeast US. He has helped in writing three research proposals submitted to NOAA/OGP program and NASA/NEWS project, and two of them were funded and one is currently pending. Publications: Lifeng Luo, Eric F. Wood and Ming Pan: A Bayesian approach for merging multi-model seasonal climate forecasts. J. Climate, in review Lifeng Luo and Eric F. Wood: Seasonal hydrologic forecasting with VIC model over the Southeastern US. To be submitted to J. Hydrometeorology. Seminar and Presentation: L. Luo, E. F. Wood, C. T. Gordon and S. L. Malyshev: Precipitation variability and potential predictability at seasonal-to-interannual timescale in the GFDL General Circulation Model, AGU, Montreal, Canada, May 2004 L. Luo and E. F. Wood: A VIC-base seasonal hydrologic forecast system over the eastern US, 2nd International workshop on HEPEX, Boulder, Colorado, July 2005 Sergey Malyshev, Research Staff Sergey Malyshev received his Ph.D. in Geophysics from Institute of Experimental Meteorology, Obninsk, Russia in 1995. His primary research interests are simulation of climate, atmospheric circulation, its coupling to the processes on the underlying land surface and to the carbon balances in the Earth system. He started working at Princeton University in 2001 as a research staff member. His current primary activity is the development and implementation of sophisticated land surface and vegetation model in the framework of Geophysical Fluid Dynamics Laboratory (GFDL) Flexible Modeling System (FMS). This is a part of a larger effort to develop a comprehensive coupled atmosphere/ocean/land climate model and Earth system model. As a result of this work, a paper describing design and performance of the new LM3V land and biosphere model has been submitted to the Global Biogeochemical Cycles and currently in review. Some exciting results regarding carbon balances, influence of atmospheric CO2 concentrations on the land biosphere, and the role of human activity have been already obtained with the new model and were presented at the Seventh International Carbon Dioxide Conference. This work continues, with the current development of land model focusing on improved representation of the soil moisture processes and associated feedbacks, and modeling river transport. He is actively participating in the development of the atmospheric/coupler components of the Earth system model. He is also involved in a project studying predictability of Earth climate on the seasonal scale, in particular the influence of soil moisture on the summer seasonal predictability. An important step in understanding of the involved feedbacks in the atmospheric models and the potential of improving seasonal forecasts was the collaborative Global Land-Atmosphere Coupling Experiment (GLACE). It resulted in a paper published in Science emphasizing potential sensitive "hot spots" of the system, and the detailed description of the findings is about to be published in the Journal of Hydrometeorology. As a continuation of this study, he now works on some aspects of the seasonal forecasting with state-of-the-art GFDL atmospheric model. Recent Publications: Anderson, J. L., V. Balaji, A. J. Broccoli, W. F. Cooke, T. L. Delworth, K. W. Dixon, L. J. Donner, K. A. Dunne, S. M. Freidenreich, S. T. Garner, R. G. Gudgel, C. T. Gordon, I. M. Held, R. S. Hemler, L. W. Horowitz, S. A. Klein, T. R. Knutson, P. J. Kushner, A. R. Langenhorst, N.-C. Lau, Z. Liang, S. L. Malyshev, P. C. D. Milly, M. J. Nath, J. J. Ploshay, V. Ramaswamy, M. D. Schwarzkopf, E. Shevliakova, J. J. Sirutis, B. J. Soden, W. F. Stern, L. A. Thompson, R. John Wilson, A. T. Wittenberg, and B. L. Wyman, 2004: The New GFDL Global Atmosphere and Land Model AM2-LM2: Evaluation with Prescribed SST Simulations. J. of Climate, 17, pp.4641-4673. Randal D. Koster, Paul A. Dirmeyer, Zhichang Guo, Gordon Bonan, Edmond Chan, Peter Cox, C. T. Gordon, Shinjiro Kanae, Eva Kowalczyk, David Lawrence, Ping Liu, Cheng-Hsuan Lu, Sergey Malyshev, Bryant McAvaney, Ken Mitchell, David Mocko, Taikan Oki, Keith Oleson, Andrew Pitman, Y. C. Sud, Christopher M. Taylor, Diana Verseghy, Ratko Vasic, Yongkang Xue, and Tomohito Yamada, 2004: Regions of Strong Coupling Between Soil Moisture and Precipitation. Science, 305, 1138-1140. D. W. Keith, J. F. DeCarolis, D. C. Denkenberger, D. H. Lenschow, S. L. Malyshev, S. Pacala, and P. J. Rasch, 2004: The influence of large-scale wind power on global climate. Proc. Nat. Academy of Science, 101(46), 16115-16120. Salvatore Manfreda, Research Associate 2001 - Degree in Civil Engineering (Hydraulics) cum lode, University of Basilicata, Italy. 2004 - Doctor of Philosophy, University of Basilicata, Italy. Salvatore Manfreda has a broad interest in hydrology and ecohydrology with particular emphasis on soil moisture dynamics, distributed modeling, rainfall modeling and flood event estimations. He is interested in continuous hydrological simulations combining stochastic rainfall models with distributed hydrological models for flood event prediction. He has developed a rainfall-runoff distributed model called DREAM that has been successfully applied over a broad number of basins in Southern Italy. His current research is focused on the description of the dynamic of soil moisture in the spatial and temporal domain through the use of a water balance model where the rainfall is represented as a stochastic process in space and time. This topic has been developed in collaboration with Ignacio Rodríguez-Iturbe deriving a simplified spatial-temporal soil moisture model driven by stochastic space-time rainfall forcing. The model is mathematically tractable, and allows to explore analytically the spatial and temporal structure of soil moisture fields, induced by the spatial-temporal variability of rainfall and the spatial variability of vegetation. The above results have then been used to derive the sampling requirements to estimate with a prescribed statistical precision the average soil moisture over a give time interval (e.g., daily) and over a given area. Recent publications: Manfreda, S. & I. Rodríguez-Iturbe. On the Spatial and Temporal Sampling of Soil Moisture Fields. (Submitted to Water Resources Research), 2005. Manfreda, S., M. McCabe, E.F. Wood, M. Fiorentino and I. Rodríguez-Iturbe. Spatial Patterns of Soil Moisture from Distributed Modeling. (Submitted to Advances in Water Resources), 2005. Rodríguez-Iturbe, I., V. Isham, D.R. Cox, S. Manfreda, A. Porporato. Space-time modeling of soil moisture: stochastic rainfall forcing with heterogeneous vegetation. Water Resources Research (in press), 2005. Isham, V., D.R. Cox, I. Rodríguez-Iturbe, A. Porporato, S. Manfreda. Representation of Space-Time Variability of Soil Moisture. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences (in press), 2005. Manfreda, S., M. Fiorentino, V. Iacobellis. DREAM: a distributed model for runoff, evapotranspiration, and antecedent soil moisture simulation. Advances in Geosciences, 2, 31–39, 2005. Manfreda, S., E.F. Wood, I. Rodríguez-Iturbe. Spatial patterns of soil moisture from distributed modeling. Geophysical Research Abstracts, Volume 7, 2005. Caylor, K.K., S. Manfreda, I. Rodríguez-Iturbe. On the coupled geomorphological and ecohydrological organization of river basins. Advances in Water Resources 28(1), 69-86, 2005. Scanlon, T.M., K.K. Caylor, S. Manfreda, S.A. Levin, I. Rodríguez-Iturbe, Dynamic Response of Grass Cover to Rainfall Variability: Implications the Function and Persistence of Savanna Ecosystems. Advances in Water Resources, 28(3), 291-302, 2005. Vaughan Phillips, Research Staff Dr V. Phillips received his PhD from the University of Manchester Institute of Science and Technology (UMIST), UK, in 2001. He worked with Professors J. Latham, A. Blyth and T. Choularton on development of an explicit microphysics model in the atmospheric physics research group of the Physics Department there. His research interests are:- cloud microphysics, conversion of aerosols to hydrometeors, cloud dynamicsmicrophysics interactions, parametrisation of deep convection in climate models, closure hypotheses for deep convection schemes linking intensity of convection to large-scale flow, and the interaction of aerosols with clouds during climate change. An exciting development this year has been his participation in a team effort to develop a “doublemoment” treatment of cloud microphysics for the deep convection and large-scale cloud parametrisations of the latest version of the GFDL General Circulation Model (GCM). The motivation for this effort is the need for a capability to predict cloud radiative properties during climate change, in response to anthropogenic modification of aerosol concentrations in the atmosphere. Such a “double-moment” representation includes prediction of particle numbers, in addition to conventional scalars of mass mixing ratio. This involves representing the natural diversity of nucleation pathways for formation of crystals and droplets. As a test-bed for development of double-moment codes for the GCM cloud schemes, a double-moment bulk microphysics scheme has been created by Dr V. Phillips for GFDL CSRMs. This scheme will soon be implemented within the framework of the Flexible Modeling System (FMS). Microphysical modules (e.g. for preferential droplet evaporation during homogeneous freezing) developed within the CSRM test-bed framework have already been applied directly to a new doublemoment version of the deep convection scheme of the GCM by Dr V. Phillips. Selected publications: J.-Y. Grandpeix, V. T. J. Phillips, and R. Tailleux “Improved mixing representation in Emanuel’s scheme”, Q. J. R. Meteorol. Soc. , 130, pp 3207 (2004) A. Khain, A. Pokrovsky, M. Pinsky, A. Seifert, and V. T. J. Phillips, “Simulation of effects of atmospheric aerosols on deep turbulent convective clouds by using a spectral microphysics mixed-phase cumulus cloud model. Part 1: Model description and possible applications”, J. Atmos. Sci., 61(24), 29632982 (2004) Y. Ming, V. Ramaswamy, L. J. Donner and V. T. J. Phillips, “A robust parametrisation of cloud droplet activation”, J. Atmos. Sci. In press (2005) V. T. J. Phillips, S. C. Sherwood, C. Andronache, A. Bansemer, W. C. Conant, P. J. DeMott, R. C. Flagan, A. Heymsfield, H. Jonsson, M. Poellot, T. A. Rissman, J. H. Seinfeld, T. Vanreken, V. Varutbangkul and J. C. Wilson, “Anvil glaciation in a deep cumulus updraft over Florida simulated with an Explicit Microphysics Model. I: The impact of various nucleation processes”, Q. J. R. Meteorol. Soc., 131, 2019-2046 (2005a) M. Salzmann, M. G. Lawrence, V. T. J. Phillips and L. J. Donner, “Modeling tracer transport by a cumulus ensemble: lateral boundary conditions and large-scale ascent”, Atmos. Chem. Phys. Discuss., 4, 3381-3418 (2004) Gwendal Rivière, Research Associate I completed my PhD at the university of Pierre et Marie Curie in Paris (France) in September 2002 on geophysical fluid dynamics where I was supervised by Drs. Patrice Klein and Lien Hua. I have then done a first postdoc at Centre National de Recherches Météorologiques in Toulouse (France) on extratropical Atlantic storms with Dr. Alain Joly. Since January 2004, I am doing a second postdoc in Princeton (USA) funded by the Atmospheric and Oceanic Sciences Program of Princeton University. I am currently working on the Atlantic Storm-track variability and trends with Dr. Isidoro Orlanski from the Geophysical Fluid Dynamic Laboratory (GFDL). The focus of my study is to better understand feedbacks of high-frequency eddy activity onto the quasi-stationary circulation, particularly with regard to the North Atlantic Oscillation (NAO) phenomenon. The NAO is the principal mode of variability of the weather and climate over the north Atlantic domain and understanding its mechanism is one of the major goals of the research community in climate sciences. Our methodology consists in analyzing observations from NCEP reanalysis data and sensitivity runs from the high resolution non hydrostatic regional model developed at GFDL that is called the ZETAC model. Consistent with recent studies, our results show that the jet displacement characteristic of the NAO phenomenon depends strongly on the dynamics of the high-frequency synoptic-scale waves and the way they break. Positive and negative phases of the NAO are closely related to anticyclonic and cyclonic wave breaking respectively. The original aspect of our work is to show with the help of sensitivity runs of the ZETAC model that wave breaking over the Atlantic is strongly sensitive to the spatial and temporal characteristics of the upper-level waves coming from the Eastern Pacific and North America. These results could lead to the identification of precursors of the different NAO phases and are thus especially important for predictability issues related to the climate in the Atlantic sector. It also can help to improve GCMs simulation of the atmospheric low-frequency variability. Before leaving GFDL at the end of the year, the rest of my work will consist in presenting the above results in papers to be submitted for a refereed journal publication as well as in seminars and conferences as it will be the case for example during the 2005 AGU Fall meeting. Joellen L. Russell, Research Staff Joellen Russell completed her Ph.D. at Scripps Institution of Oceanography, UCSD in July 1999. She was then appointed a postdoctoral research fellow at the Joint Institute for the Study of Atmosphere and Ocean at the University of Washington where she worked with Professor J.M. Wallace. In September of 2002, she arrived at Princeton University as a postdoctoral visiting scientist in the AOS Program, jointly sponsored by Princeton University and GFDL/NOAA, working with Dr. J.R. Toggweiler. She now works as a Research Staff member of Princeton University, collaborating with Robbie Toggweiler, Ronald Stouffer, Keith Dixon and Anand Gnanadesikan at GFDL/NOAA and Stephen Pacala, Elena Shevliakova and Sergey Malyshev at Princeton University. Dr. Russell's research focuses on the carbon cycle impacts of the changes in the Westerly Winds, which have moved poleward and increased over the last 30 years in both hemispheres, possibly as the first and most ferocious of the impacts of global warming. She documented the impact of this shift in the Northern Annular Mode on the northern hemisphere terrestrial vegetation and its subsequent impact on atmospheric carbon dioxide and is collaborating with Elena Shevliakova, Sergey Malyshev and Stephen Pacala at Princeton University to examine this process in the LM3V dynamic vegetation model. Dr. Russell is also working on the impact of the shift of the wind over the Southern Ocean in creating and destroying the water masses critical to the global carbon cycle, ocean circulation, and heat budget. The Southern Ocean acts as the lungs of the ocean, "inhaling" oxygen and "exhaling" carbon dioxide (CO2) - determining the partition of carbon between atmosphere and ocean. In pursuit of this research, Dr. Russell uses (and when possible, collects) in situ and satellite measurements of the atmosphere, the ocean, and ocean bottom sediments. She interprets these data using statistical analyses, ocean general circulation models, and coupled climate models. Related Publications: Russell, J.L., & J.M. Wallace (2004), Annual carbon dioxide drawdown and the Northern Annular Mode, Global Biogeochem. Cycles, 18, GB1012, doi:10.1029/2003GB002044. Russell, J.L., R.J. Stouffer & K. Dixon, Intercomparison of the Southern Ocean Circulations in the IPCC Coupled Model Control Simulations. J. Climate, accepted. Russell, J.L., & J.M. Wallace, Carbon Dioxide Variability, Fire and ENSO Examined with a Simple, One-Year Filter. Global Biogeochem. Cycles, accepted. Delworth, T.L., et al., GFDL's CM2 Global Coupled Climate Models-Part 1: Formulation and Simulation Characteristics. J. Climate, in press. Gnanadesikan, A., et al., GFDL's CM2 global coupled climate models-Part 2: The baseline ocean simulation. J. Climate, in press. Griffies, S.M., A. Gnanadesikan, K.W. Dixon, J.P. Dunne, R. Gerdes, M.J. Harrison, A. Rosati, J.L. Russell, B.L. Samuels, M.J. Spelman, M. Winton, and R. Zhang, 2005: Formulation of an ocean model for global climate simulations , Ocean Science , 1, 45-79, 2005. Toggweiler, J.R., J.L. Russell & S.R. Carson, The Mid-Latitude Westerlies, Atmospheric CO2, and Climate Change during the Ice Ages, Paleoceanography, accepted. Russell, J.L., K. Dixon, A. Gnanadesikan, R. Stouffer & J.R. Toggweiler, The Southern Hemispherre Westerlies in a Warming World: Keeping the Door Open to the Deep Ocean. GRL, submitted. Russell, J.L., A. Gnanadesikan & J.R. Toggweiler, Impact of Westerly Wind Position on the Circulation of the Southern Ocean. J. Climate, in review. Elena Shevliakova, Research Staff Elena Shevliakova graduated from Moscow Institute of Physics and Technology in 1990, where she studied applied physics and mathematics with the concentration on the ocean acoustics. She received her Ph.D. from Carnegie Mellon University (CMU) in 1996. She was appointed a post-doctoral research fellow at the CMU Center for Integrated Study of the Human Dimensions of Global Change where she continued her research on application of statistical methods for modeling the impacts of climate change on terrestrial distributions of vegetation. In 1999 she joined Department of Ecology and Evolutionary Biology at Princeton University as a research stuff member of Dr. Pacala laboratory. Dr. Shevliakova's research focuses on the study of the global biosphere-climate interactions, with the emphasis on development of biosphere models and their applications to the issues of global environmental change. For the past 5 years she worked toward understanding of physical, ecological and biogeochemical aspects of land surface dynamics. During this time she served as a co-leader of the GFDL-Princeton University land model development team and worked on the implementation and evaluation of the new dynamic global land model LM3V. She is planning to use the new model to systematically examine the terrestrial carbon dynamics, the ecological impacts of climate change and the biosphere feedbacks on climate. She is collaborating with a number of scientists at GFDL, Princeton University and University of New Hampshire on the implementation and development of new capabilities in the land model and its integration into the GFDL Earth System Model. Related Publications: Shevliakova, E., S.W. Pacala, S. Malyshev, G.C. Hurtt, P.C.M. Milly, J. P. Caspersen, P.C.D. Milly, L. Thompson, C Wirth and K.A. Dunne (2005). "The Land Carbon Cycle and Vegetation Dynamics in the Global Dynamic Land Model LM3V", submitted to Global Change Biology. Hurtt, G.C., S. Frolking, M. G. Fearon, B. Moore III, E. Shevliakova, S. Malyshev , S. Pacala , R. A. Houghton (2005). The underpinnings of land-use history: three centuries of global gridded land-use transitions, wood harvest activity, and resulting secondary lands, submitted to Global Change Biology. Shevliakova (2002). "Modeling Potential Impacts of Climate Change on the Spatial Distribution of Vegetation in the US with A Probabilistic Biogeography Approach", in Wildlife responses to Climate Change: North American Case Studies, Eds. S. Schnider and T. Root, Island Press. Delworth, T.L. A. J. Broccoli, A. Rosati, R. J. Stouffer, V. Balaji, J. T. Beesley, W. F. Cooke, K.W. Dixon, J. Dunne, K. A. Dunne, J W. Durachta, K.L. Findell, P. Ginoux, A. Gnanadesikan, C.T. Gordon, S.M. Griffies, R. Gudgel, M. J. Harrison, I.M. Held, R. Hemler, L. W. Horowitz, S. A. Klein, T.R. Knutson, P.J. Kushner, A. L. Langenhorst, H.-C. Lee, S.J. Lin, J. Lu, S. L. Malyshev, P.C. Milly, V. Ramaswamy, J. R. , M. D. Schwarzkopf, E. Shevliakova, J. Sirutis, M. Spelman, W. F. Stern, M. Winton, A. T. Wittenberg, B. Wyman, F. Zeng, R. Zhang, 2005. "GFDL's CM2 Global Coupled Climate Models - Part 1: Formulation and Simulation Characteristics", (accepted to Journal of Climate). Jennifer Simeon, Professional Technical Staff I graduated with a M.S. in Oceanography from Oregon State University. I am interested in utilizing ocean tracers as a tool for understanding ocean circulation, as well as ocean-atmosphere interaction. My graduate studies focused upon developing optical tracers to investigate flows on a continental shelf. My current research concerns the Sub-Antarctic Mode Water (SAMW) formation and pathways. Using tracers within a suite of models that has varying global overturning circulation states, these potential scenarios are explored to gain insight for the ocean response to climate change. Publications: Simeon, J., C. Roesler, W.S. Pegau, and C. Dupouy (2003). Sources of spatial variability in light absorbing components along an equatorial transect from 165E to 150W, J. Geophys. Res., 108:C10, 3333, doi: 10.1029/2002JC001613. Richard Slater, Prof. Technical Staff I grew up in northern Illinois and attended college at Florida Institute of Technology from 1975-79, majoring in physical oceanography. I began my career in “numerical oceanography” by studying the tides in the Indian River in Melbourne, Florida. I performed a numerical analysis of the tides using data obtained from a tide gauge housed in the Crew team’s boathouse. I became involved in numerical modeling when I attended the University of Chicago, working with Professor George Platzman on my Master’s thesis: A Numerical Model of Tides in the Cretaceous Seaway of North America. During my graduate school days, I spent two summers working at Exxon Production Research Company in Houston, Texas where I did some research on dissolved oxygen distributions and organic carbon deposition in the Arabian Sea. My interests now turning away from tides and towards biological and chemical oceanography modeling, I started my Ph.D. thesis work on a model of oxygen in the ocean. In 1984 I moved to Princeton, working for Professor Jorge Sarmiento, both as job and to work more on my dissertation research. However, I never did get working on my dissertation research and have been here ever since. I attribute that mostly to having a job doing what I wanted to do, anyway (but it could always be a little laziness on my part—nah). In April of 1988, we started collaborating with Mike Fasham on ecosystem modeling, and shortly thereafter, I had the Fasham model running in our 2-degree North Atlantic oceanic general circulation model (OGCM). Since then, there has been much modeling of biology and chemistry put into our various OGCMs. Recent technical work I have been doing has related to putting a generalized method to incorporate tracer models into the Geophysical Fluid Dynamics Laboratory‘s (GFDL) Flexible Modeling System (FMS)—basically, the Modular Ocean Model 4 (MOM4). Qian (Scott) Song, Research Associate Ph. D. in Physical Oceanography, Columbia University, 2004 M. Ph. in Physical Oceanography, Columbia University, 2003 M. A. in Physical Oceanography, Columbia University, 2001 B. S. in Oceanography, Ocean University of Qingdao, 1997 Since joining GFDL in July 2004, I have been working with Anthony J. Rosati on three projects using the GFDL CM2.x coupled climate model. Detailed description of the projects is as follows. (1) Assessment of the CM2 coupled climate model simulation of the North Pacific. This project is part of the laboratory’s effort to evaluate the newly developed CM2 coupled models in simulating the current climate system. My research is focused on the model simulation of the North Pacific Ocean. The conclusions of this study are on the strength and weakness of the CM2.x models in simulating the North Pacific climatology. In particular, we find the models produce reasonable oceanic mass and heat transport, and due to the use of finite volume dynamic core in CM2.1 there is substantial improvement in representation of the polar fronts and the subtropical gyre circulation over CM2.0. However, there are biases of too diffused thermocline, deep winter mixed layer south of Kurishio and large volume of the Subtropical Mode formation in the two models. (2) Indian Ocean variability in the GFDL coupled model. The 300-yr 1990-control simulation in CM2.1 provides an excellent opportunity for us to study the dynamics of the interannual and decadal variabilities in the Indian Ocean. Our study is focused on the Indian Ocean Dipole/Zonal Mode (IODZM), which is associated many debates about its air-sea coupled dynamics and its relation with ENSO and is of much interest in the Indian Ocean research community. We perform a composite analysis to explore the ENSO-IODZM relation. We find that the westerly wind anomalies in the Western Equatorial Pacific, although may not be able to evolve into full El Nino events, is effective in triggering the development of IODZM events. We also propose that tropical storms occurring during boreal summer in the Eastern Tropical Indian Ocean may be a mechanism that prevents the development of IODZM events when El Nino occurs in the Pacific. The decadal modulation of the occurrence of IODZM events is also investigated. (3) Effects of the ITF on the global climate. Most previous studies on the ITF effects are conducted in ocean-only models. The few coupled model studies only discussed the mean state difference ITF causes due to their short model integration. We perform a perturbation experiment using the same model setting as the CM2.1 1990-control experiment, except that the ITF is blocked. By contrasting the control experiment and the perturbation experiment we study the ITF effects on the mean state, seasonal cycle and interannual variability of the climate system. J. Jason West, Research Staff J. Jason West conducts interdisciplinary research addressing atmospheric chemistry, and science and policy aspects of air quality management and climate change. He came to Princeton in October, 2004, to work with V. Ramaswamy and Denise Mauzerall of Princeton’s Woodrow Wilson School of Public and International Affairs. He has also worked closely with Arlene Fiore and Larry Horowitz of GFDL. His main research interest has been in exploring whether methane emission reductions can be justified due to their decreases in global background concentrations of tropospheric ozone. A first paper on this topic (West & Fiore, 2005) showed that implementing low-cost methane reductions using identified technologies can significantly reduce global background concentrations of ozone, with substantial benefits to human health and agriculture. This work has been extended over the past year by using the MOZART-2 global atmospheric chemistry model to estimate the effects of a 20% reduction in anthropogenic methane emissions on surface ozone concentrations, finding a reduction of ~1 ppbv. These changes in surface concentrations were then used to estimate the avoided incidences of premature human mortality, using ozone-mortality relationships from recent epidemiological studies. We find that ~30,000 premature mortalities can be avoided in the year 2030, and that when these benefits are monetized, they give ~$12 per ton CH4, which can justify the 20% methane reduction. Our ongoing research has continued this theme by comparing the effects of reductions in emissions of four ozone precursors (CH4, NOX, CO, and NMVOCs) on both surface ozone concentrations and on radiative forcing of the global climate. In addition to this research, Dr. West has contributed to two review papers addressing the international transport of air pollutants. Publications: West, J. J., and A. M. Fiore (2005) Management of tropospheric ozone by reducing methane emissions Environmental Science & Technology, 39(13): 4685-4691, doi: 10.1021/es048629f. West, J. J., A. M. Fiore, L. W. Horowitz, and D. L. Mauzerall (submitted) Mitigating ozone pollution with methane emission controls: global health benefits, Proceedings of the National Academy of Sciences. West, J. J., A. M. Fiore, V. Naik, L. W. Horowitz, D. L. Mauzerall (in preparation) Response of surface ozone concentrations and radiative climate forcing to changes in ozone precursor emissions. Bergin, M., J. J. West, T. J. Keating, and A. G. Russell (in press) Regional atmospheric pollution and transboundary air quality management, Annual Review of Environment and Resources. Keating, T., J. West, and D. Jaffe (2005) Air quality impacts of intercontinental transport, EM (Environmental Management), 28-30, Oct., 2005. Conference Presentations: West, J. J., A. M. Fiore, L. W. Horowitz, D. L. Mauzerall ‘Control of methane emissions for ozone air quality: global health benefits,’ MOZART Users’ Meeting, Aug. 2005, Boulder, CO. West, J. J., A. M. Fiore, L. W. Horowitz, D. L. Mauzerall ‘Global health benefits from reductions in background tropospheric ozone due to methane emission controls,’ AGU 2005 Joint Assembly, #A51B06, May 2005, New Orleans, LA. West, J. J., A. M. Fiore, L. W. Horowitz, D. L. Mauzerall ‘Control of methane emissions for ozone air quality purposes,’ Air Pollution as a Climate Forcing, A Second Workshop, Apr. 2005, Honolulu, HI. West, J. J., A. M. Fiore ‘Reducing tropospheric ozone through methane mitigation: costs and benefits,’ American Geophysical Union Fall Meeting, #A23A-0770, Dec. 2004, San Francisco, CA. Youlong Xia, Research Staff I arrived at CICS of Princeton and NOAA Geophysical Fluid Dynamics Laboratory (GFDL) in December of 2003. Since then I have published five papers and submitted one paper (in revision). In CICS, I am focusing on my research project, building a realtime national streamflow information system for the US, based on the GFDL LaD (Land Dynamics) model (LM2p7 and LM3w) and NASA NLDAS (North American Land Data Assimilation System) data set. This project will provide provide a streamflow information system to meet society’s needs for water resource management and use. Calibration of GFDL land models (LM) is important for establishing a Real-time National Streamflow Information System and for development of the GFDL coupled climate model. Both old (LM2) and new (LM3) versions of the GFDL LM have many uncertain and unmeasureable model parameters. The purpose of calibrating GFDL LMs is to reduce the uncertainties of these model parameters and to obtain best performance for our research purposes. To overcome disadvantages and limits of the manual calibration method used by Milly and Shmakin (2002), we applied an automatic calibration method (very fast simulated annealing, or VFSA) to tune GFDL LMs. To ensure the reliability and efficiency of the algorithm for our application, we have performed many sensitivity tests with respect to VFSA parameters. Additionally, Xia has used this algorithm to develop new methods to correct precipitation bias arising from gauge undercatch and orographic effect, respectively. These methods integrate VFSA, LM2, and observed streamflow, and have been applied on national and global scales. This method has been tested in the east of the United States by use of the NLDAS (North Land Data Assimilation System) data set for the period from 1997 to 2002. The results show that this method is able to correct gauge bias caused from wind-blowing, wet loss and evaporation loss. A manuscript has been submitted to JGR-atmosphere (in revision). For global topographic effect on precipitation data, a topographic bias adjustment method combining VFSA, LM2, observed streamflow, and topographic variance is used. The primary results show that this method can adjust topographic bias for global precipitation data because comparison of corrected precipitation and PRISM (see http://www.ocs.orst.edu/prism/) data is very consistent. The draft about this work is progressing. These methods reduce forcing data errors (i.e., precipitation) and improve streamflow simulations in the United States and globally. At the same time, GFDL land dynamics model (LM2) is also well optimized. This optimization technique and work experiences from LM2 work now are being transferred to optimize a preliminary version of the new GFDL land model (LM3W) with respect to hydrological and soil physics processes. Eventually, this algorithm can be used to tune new land-vegetation dynamics model (LM3) consisting of LM3W used as water component and LM3V used as dynamic vegetation component. Recent Publications: Xia, Y., Z. L. Yang, P. L. Stoffa, M. K. Sen, 2005a: Using different hydrological variables to assess the impacts of atmospheric forcing errors on optimization and uncertainty analysis of the CHASM surface model at a cold catchment, J. Geophys. Res., 110, D01101, doi:10.1029/2004JD005130. Xia, Y., 2005: Optimization and Uncertainty Estimates of WMO Regression Models for Precipitation-Gauge Bias in the United States, J. Geophys. Res. (in revision). Jianjun Yin, Research Associate Jianjun Yin received his Ph.D from University of Illinois at UrbanaChampaign in October 2004, majoring in climate dynamics and modeling. He arrived at AOS/GFDL in fall 2004 as a postdoctoral research associate, working primarily with Ronald Stouffer and also with several other scientists at GFDL. Jianjun’s research subject is the Atlantic Thermohaline Circulation (THC). So far he has finished one project and has two ongoing ones. Since his arrival, Jianjun has intensively participated in the data analyses of the CMIP/PMIP coordinated “water-hosing” experiments. These experiments were designed to systematically study the sensitivity of the THC to external freshwater forcings. Jianjun, together with other co-workers, has intercompared the simulations by 14 climate models worldwide, and evaluated the robustness of particular features across the model results. The uncertainties in modeling the THC have been greatly reduced in the multi-model ensemble mean. A paper describing the findings has been accepted by Journal of Climate for publication. Jianjun is currently leading two other projects: evaluating the uncertainty induced by the virtual salt flux assumption in the climate simulations and studying the stability of the THC under very large freshwater perturbations. He has found that a virtual salt flux version of the GFDL CM2.1 can give remarkably similar simulations about the climate and climate changes with those from a freshwater flux version. But some notable difference has still been identified. A paper that documents the findings is to be submitted to Journal of Physical Oceanography. A CMIP “partially-coupled” experiment with the GFDL CM2.1 has also been planed as one of Jianjun’s research activities at AOS/GFDL. Publications: J. Yin, R. J. Stouffer, M. J. Spelman and S. M. Griffies: Evaluating the Uncertainty Induced by the Virtual Salt Flux Assumption in the Climate Simulations and Projections with a Coupled AtmosphereOcean General Circulation Model. Journal of Physical Oceanography (To be submitted). R. J. Stouffer, J. Yin, J. M. Gregory, K. W. Dixon, M. J. Spelman, W. Hurlin, A. J. Weaver and participating groups: Investigating the Causes of the Response of the Thermohaline Circulation to Past and Future Climate Changes. Journal of Climate (In press). Rong Zhang, Research Staff Rong Zhang completed her Ph.D. at Massachusetts Institute of Technology in September 2001. In January 2002 she arrived at Princeton University as a postdoctoral visiting scientist in the AOS Program, jointly sponsored by Princeton University and GFDL/NOAA, working with Dr. Geoffrey Vallis at the AOS Program. Since January 2004, she worked as a Research Staff Member of Princeton University, collaborating with Dr. Geoffrey Vallis at the AOS Program and Dr. Thomas Delworth at GFDL/NOAA. She worked on three major research projects. In the first project, Rong Zhang and Geoffrey Vallis explored the mechanism of the Gulf Stream separation and the existence of cyclonic Northern Recirculation Gyre (NRG) with a simple coupled model and developed a theory identifying the ocean bottom vortex stretching induced by downslope deep western boundary current (DWBC) as the key mechanism. In the second project, Rong Zhang and Geoffrey Vallis found that coherent large-scale low frequency variability in the North Atlantic, including variations of thermohaline circulation, DWBC, NRG and Gulf Stream path, can be induced by the observed highlatitude oceanic Great Salinity Anomaly events; on multidecadal timescales the positive (negative) Great Salinity Anomaly phase, associated with more (less) Iceland sea ice extent, leads Labrador Sea surface cooling (warming) and a positive (negative) North Atlantic Oscillation phase. The multidecadal variations of the Iceland sea ice extent may have contributed to the observed Atlantic Multidecadal Oscillation (AMO). In the third project, using a newly developed coupled ocean-atmosphere model (GFDL CM2.0), Rong Zhang and Thomas Delworth investigated the global scale response of the climate system to a substantial weakening of the Atlantic thermohaline circulation. The global response involves a southward shift of the intertropical convergence zone (ITCZ) over both the Atlantic and Pacific sectors, an El Nino like condition in the southern tropical Pacific, a La Nina like condition in the northern tropical Pacific, and weakened Indian and Asian summer monsoons, consistent with the global-scale synchronization of millennial-scale abrupt climate change as indicated by paleoclimate records. Recently, Rong Zhang and Thomas Delworth have been working on a new project, i.e. the impact of Atlantic Multidecadal Oscillation (AMO) on the 20th century climate variability. Recent Publications: Zhang, R., and T. Delworth, 2005: Simulated Tropical Response to a Substantial Weakening of the Atlantic Thermohaline Circulation. Letter in Journal of Climate, 18, 1853-1860 . Zhang, R., and G. K. Vallis, 2005: Impact of Great Salinity Anomalies on the Low Frequency Variability of the North Atlantic Climate. Journal of Climate. In Press. Zhang, R., and G. K. Vallis, 2005: The Role of the Deep Western Boundary Current in the Separation of the Gulf Stream. Journal of Physical Oceanography. Under Review. Research Grant: Co-PI of the NSF grant OCE-0351383: Mechanisms of Decadal Variability in the North Atlantic: The Thermohaline Circulation, Great Salinity Anomalies, and Gulf Stream Path. Awarded by NSF OCE in Feb. 2004, and funded for three years with total of $ 444,253. Ming Zhao, Research Associate Ming Zhao received his PhD from the University of British Columbia in September, 2003. During his PhD work, Ming was involved in a Canadian project “Modeling Clouds and Climate (MOC2)”. After his PhD, he continued his work for MOC2 in Canadian Centre for Climate Modeling and Analysis (CCCma) from Oct. 2003 to Jan. 2004. Starting from Feb. 2004, Ming joined the GFDL Climate Process Team (CPT) and has been serving as the GFDL's liaison to the atmospheric CPT project on “LowLatitude Cloud Feedbacks on Climate Sensitivity”. Ming’s research interests include atmospheric moist convection, clouds and their representations in large-scale and global climate models. Ming’s work includes both supporting and original research components. Ming supports the GFDL participation in the atmospheric CPT by providing a variety of GFDL model output, carrying new simulations, analysis, implementing and testing new parameterization schemes in GFDL AM2. He also created and maintained a CPT@GFDL web-page to assemble simulation data, display results and efficiently communicated with the rest of CPT. Please see http://www.gfdl.noaa.gov/~miz for a detailed description of the projects that Ming has been working on. Under the supervision of Isaac Held, Ming is also pursuing original researches on simulations of largescale tropical atmospheric circulation with idealized configurations. They include dynamical radiativeconvective equilibrium, non-rotating mock Walker circulation and aqua-planet Hadley circulation simulations. These idealized experiments are part of our effort to bridge the gap between our understanding and the ever-complicated climate simulation. Comparing different GCMs in these idealized simulations may offer new and simpler ways to highlight and understand the model differences. Publications: Wyant, M. E., C. S. Bretherton, J. T. Bacmeister, J. T. Kiehl, I. M. Held, M. Zhao, S. A. Klein, and B. A. Soden, 2005: A comparison of tropical cloud properties and responses in GCMs using midtropospheric vertical velocity. Climate Dyn., submitted 8/05. Held, I, M, M. Zhao and B. Wyman 2005: Radiative-convective equilibrium using GCM column physics, J. of Atmos. Sci., to be submitted. Zhao, M, I. M. Held and B. Wyman 2005: The role of atmospheric cloud radiative forcing in an idealized Hadley circulation, manuscript in preparation. Rongrong Zhao, Research Associate Before being a postdoctoral researcher of Program in Atmospheric and Oceanic Sciences in December 2004, I was a doctoral candidate in Mechanical and Aerospace Engineering Department of Princeton University. The title of my Ph.D dissertation is “High Reynolds Number Turbulent Pipe Flow”. This is a project funded by Office of Naval Research (ONR). High Reynolds number flow is of extreme research interest because many industrial flows and most geophysical flows are of this kind, but at the same time, reliable measurement results are very limited. The study is done in Princeton Superpipe (a major facility in the nation for high Reynolds number flow research), where I used miniature two dimensional hot-wire to measure turbulence quantities up to Reynolds number of ReD=1x107. This is the highest Reynolds number ever achieved for the pipe flow, and the data is expected to serve as a reference data set for the development of numerical simulation and predictive methods for turbulence. Along with turbulence research, I am also very interested in improvement of measurement techniques. I developed a new calibration method for crossed hot-wire probe (one of the major measurement methods for turbulence), and the new method is believed to be more accurate than traditional calibration methods. I also pointed out an important measurement uncertainty in hot-wire experiments, which is often neglected by peer experimentalist but can lead to significant error in certain flow conditions. Both are published in peer reviewed journals. I received my Ph.D from Princeton University in January 2005. Following my doctoral work, I joined GFDL in the hope of contributing my knowledge in turbulence to the ocean and climate community. The project I am working on now is to develop suitable parameterization of mesoscale eddies for upper ocean boundary. The flow in the top ocean receives much attention from the scientists because it is the region where the coupling between ocean and atmosphere happens and most numerical problems are encountered for current climate model. This work is a part of CPT-EMILIE (Climate Prediction Team on Eddy-MIxed Layer IntEraction), which is established by the U.S. CLIVAR program for linking process-oriented research and coupled climate model development. In more detail, I use GFDL modular ocean model (MOM) to compute different idealized ocean domains. By that, I study 1) the effects of eddies on the ocean mean circulation and 2) the dynamics of the interaction between mesoscale eddies and boundary layer turbulence. I am running numerical simulations with both high spatial resolutions and low spatial resolutions. High spatial resolution results are considered as more realistic and used to study the dynamics of eddies. Low spatial resolution models are run with typical spatial resolutions that is used in current climate model to target problems. The ultimate goal is to develop physically sound subgrid scale parameterization for eddies and turbulence and improve climate models. Publications: Rongrong Zhao and Alexander Smits, Two dimensional turbulence statistics in high Reynolds number turbulent pipe flow. In preparation for J. Fluid Mech. Rongrong Zhao and Alexander Smits, Binormal cooling effects for hot-wire measurement. Experimental fluid mechanics, To appear. Rongrong Zhao, High Reynolds Number Turbulent flow. Ph.D thesis, Princeton University, 2004 Rongrong Zhao, Junde Li and Alexander Smits, A New calibration method for crossed hot wires, Meas. Sci. Technol. 15 No 9, 1926-1931. Graduate Student Bios Gang Chen, Graduate Student I am a 4th year graduate student in the AOS program. My interest is the theory and modeling of the atmospheric general circulation. More specifically, my thesis topic is to study the factors that control the midlatitude jet stream and the surface westerly positions. In the atmospheric general circulation models (GCMs), the mid-latitude jet in the southern hemisphere displays a robust poleward shift in response to the global warming. This shift of zonal wind, projected strongly onto the Southern Annular Mode (SAM), is simulated by a large number of GCMs as well as seen in the observation. Despite this problem has been investigated in relatively simple idealized models, it still remains a challenge to identify and isolate cleanly their underlying mechanisms. The current work aims to explore the simplest case of the jet shift with the surface friction, and hope to understand the factors determining the jet position in the global warming simulations in a hierarchy of models. We employ the GFDL atmospheric dynamical core forced by the Held-Suarez forcing available in the Flexible Modeling System (FMS). As the surface friction is reduced, the mid-latitude jet displaces poleward analogous to the global warming response. The effect of the surface friction is separated as the friction on the zonal means and the friction on the eddies, and the poleward shift is found to be primarily controlled by the friction on the zonal means. In addition, reducing the surface drag permits the development of stronger barotropic flow that suppresses the mid-latitude eddies. More detailed investigation indicates that the barotropic flow and the phase speed of the large scale eddies play important roles in the jet shift. The gravity wave drag (GWD) can also cause the poleward jet shift, implying the need of appropriate GWD parameterizations in tuning the GCMs. This result is to be further studied with the realistic spatial distributions of the topography and the jet stream. The nature of the jet shift involves the internal variability of the atmosphere. The first Empirical Orthogonal Function (EOF) of zonal wind variations is often called the annular mode, and is an indicator of climate change. We are currently developing a simple quantitative theory for the jet shift as well as the annular modes. The notion is to idealize the upper troposphere as one shallow water isentropic layer forced by the stochastic stirring. The simple model provides us some insights on the problem of the jet shift in the development of GCMs. Neven S. Fučkar, Graduate student Ph.D. candidate, AOS Program, Princeton University M.S. in Oceanography, Texas A&M University, 2003 B.S. in Physics, University of Zagreb, Croatia, 2000 The world oceans exert significant influence on the climate. In concert with the atmosphere through lateral (primarily meridional) and vertical transport of heat, freshwater and critical chemical tracers the oceans make the Earth hospitable to our global society in the present state. In such a planetary scale mosaic interesting and yet not completely resolved question is the nature of interaction of ocean meridional overturning circulation (MOC) and the largest ocean current in the world, the Antarctic Circumpolar Current (ACC). My most recent research, under the supervision of Prof. Geoffrey K. Vallis, among other things addresses the question of impact of MOC on the dynamics of ACC transport in an idealized coarse-resolution ocean model. Currently, at the nexus of method is the use of the Modular Ocean Model version 4.0c (MOM4) with analytically prescribed direct (wind stress) and restoring (temperature and virtual salinity) surface boundary conditions. We began working with a single-basin configuration that includes the Southern Ocean (SO) channel with a sill. Interesting result is substantial sensitivity of the ACC transport to the Northern Hemisphere meridional temperature gradient (besides previously established sensitivity to the SO winds). As the gradient decreases ACC transport increases. Hence this research represents an opportunity to further understand and separate dynamical and thermodynamical mechanisms of ACC transport and variability. In the near future we plan to use also the Hallberg Isopycnal Model (HIM) to establish the level of robustness of these conclusions by comparing z-level and isopycnal model results. Ultimately, we intend to explore this point further with a hierarchy of idealized atmosphere-ocean-ice coupled models. Resolving how these results fit into the overall picture of global climate and their implication for understanding of paleoclimate records will benefit development of ocean and climate dynamics theory and advance models. Also this progress could potentially enhance climate predictability and clarify aspects of global climate change. Edwin Gerber, Graduate Student Applied and Computational Mathematics Program, Princeton University B.S. Mathematics and Chemistry, 2000 University of the South M.A. Applied Mathematics, 2002 Princeton University Mr. Gerber is pursuing his PhD thesis on intraseasonal variability in the atmosphere with Geoffrey Vallis. He has developed a hierarchy of models of the North Atlantic Oscillation (NAO) and annular modes, the dominant large scale patterns of intraseasonal variability in the extratropics, with the goal of better understand their spatial and temporal structure. Mr. Gerber began his research with Dr. Vallis in early 2002, and plans to complete his dissertation in December 2005. They have applied a bracketing strategy to the problem, in which a range of idealized models were developed to explain key features of the variability. By adding and subtracting different elements of the dynamics, they were able to isolate the essential processes that govern the patterns. A barotropic model of the atmosphere was the starting point of their research, capturing both the basic spatial and temporal structure of the NAO and annular modes. The model suggest that both are a direct consequence of the “stirring” of the large scale flow by baroclinic eddies. The mode explicitly shows how such stirring, as represented by a simple random forcing in the model, leads to a variability in the zonal flow via a variability in the eddy momentum flux convergence. If the stochastic forcing is statistically zonally uniform, then the resulting patterns of variability (i.e., the empirical orthogonal functions, EOFs) are zonally uniform and the pressure pattern is dipolar in the meridional direction: an annular mode. If the forcing is enhanced in a zonally localized region, thus mimicking the effects of a storm track over the ocean, then the resulting variability pattern is zonally localized, resembling the NAO. This suggests that the NAO and annular modes are produced by the same mechanism, and are manifestations of the same phenomenon. The timescale of variability of the patterns is longer than the decorrelation timescale of the stochastic forcing. This is a consequence of the fact that these patterns characterize the zonal momentum in the atmosphere, the integral of the eddy momentum fluxes. Integration strengthens the power of low frequencies, which are ultimately truncated by friction to produce a red spectrum similar to that observed. Results from the study of the barotropic model indicated that the basic spatial structure of the patterns, in particular the meridional dipole of geopotential height and zonal velocity, could be explained in a more idealized context. Gerber developed a series of analytic, purely stochastic models that show that the spatial structure of the NAO and annular modes is a natural consequence of the conservation of mass and zonal momentum and geometric constraints of the extratropical circulation. Lastly, Gerber and Vallis have sought to verify the conclusions from the stochastic and barotropic models in a dry primitive equation general circulation model. Annular mode and NAO-like patterns are found by varying the degree of zonal asymmetry of the model's synoptic variability (that is, the model's storm track) with idealized topography and heating anomalies designed to approximate land-sea contrast. Only with the confluence of the right thermal and topographic forcing does a truly localized NAO-like pattern appear. This NAO can be further understood in the context of the eddy life cycle; maximum variability of the zonal flow is found in the exit region of the storm track, where eddy decay (and hence eddy momentum fluxes) dominate. In this region the eddy driven jet can more fully separate from the subtropical jet. This separation and merger is, in essence, the NAO. The temporal structure of primitive equation model is richer than the barotropic model, as it is "self stirring," producing its own baroclinic instability which can interact with the large scale variability. This interaction extends the persistence of the annular modes and NAO though a feedback between the eddies and large scale flow. Mr. Gerber is currently probing the sensitivity of this feedback to the model's thermal forcing and to topography. Arno C. Hammann, Graduate Student Program in Atmospheric and Oceanic Sciences Princeton University, Princeton NJ B.A. in Geography University of Cambridge, Cambridge, UK (2002) My research in the past year was concerned with the dynamics and thermodynamics of the annual cycle (of ocean temperatures, currents, and winds) in the tropical Pacific Ocean. While the interannual variability in this region (El Niño-Southern Oscillation, ENSO) has been receiving a lot of attention from the climate research community, many aspects of the annual cycle are still poorly understood. A better understanding, however, is crucial both with respect to the interaction of the annual cycle with the mean climate state and with ENSO-scale variability. In particular, current state-of-the-art coupled climate models continue to exhibit biases in the mean climate state in the tropical Pacific and unrealistic annual cycles involving, among others, a ‘double’ Intertropical Convergence Zone (ITCZ). My research under the supervision of Prof. S. George Philander and Prof. Anand Gnanadesikan used the CM2.1 coupled climate model developed at the Geophysical Fluid Dynamics Laboratory (GFDL) to investigate the relative importance of diabatic and adiabatic processes in driving the annual cycle. While it is clear that diabatic forcing (ultimately, solar radiation) sets the pace of the annual cycle, the largest fraction of heat fluxes in the ocean results from internal ocean dynamics. It has previously been recognized that the annually varying upwelling through the thermocline (forced by the annual cycle in winds) is a dominant mechanism. However, it has become clear now that a second mechanism is equally important: meridional movement of the equatorial cold tongue. The interplay of these two processes is crucial in allowing an annual cycle to be forced at all at the equator, where the annual solar forcing actually vanishes. Yi Huang, Graduate Student I’m a third-year Ph.D. student of the Program in Atmospheric and Oceanic Sciences of Princeton University. My research interest is Climate Sensitivity, how the complex climate system responses and equilibrates with respect to both natural and anthropogenic forcings and how different climatic components exert their roles in the process. This falls in the first of the CICS themes, Earth System Studies/Climate Research. The research I’ve been carrying on is about the roles of atmospheric temperature and water vapor in influencing the Radiative Energy Budget at the Top of the Atmosphere. Under clear-sky condition, atmospheric temperature and water vapor are two major factors that affect the Outgoing Longwave Radiation (OLR). The spectral dependence of OLR upon the vertical distributions of the two factors is a key element in the understanding of their influence on the longwave radiation budget of the planet. Using the Geophysical Fluid Dynamics Laboratory (GFDL)’s line-by-line (LBL) radiative transfer model as well as the GFDL climate model’s longwave radiation parameterization, I examined the OLR sensitivities to temperature and water vapor (defined as the partial differentials of OLR with respect to the variables), for three typical atmospheres: tropics, mid-latitude summer and mid-latitude winter. The principle findings are: 1). Results of OLR sensitivity do not differ with the longwave band approximation, nor different formulations of water vapor continuum absorption cause significant difference in simulated OLR sensitivity. 2). Shown in a GCM (General Circulation Model) climate sensitivity experiment, although the inclusion of water vapor continuum is indispensable to properly simulate clear-sky OLR response to prescribed sea surface temperature change, different continuum formulations yield negligible difference. 3). The numerically calculated OLR sensitivity values are used to reconstruct the tropical annual mean OLR anomaly from the anomalies of the surface and atmospheric conditions over the 1980-1999 period. The OLR anomaly time series thus reconstructed agrees very well with that computed explicitly by climate model. 4). The above finding enables the separation and analysis of the temperature and water vapor contributions to the OLR variation, which shows that, in the lower and middle troposphere, temperature contribution dominates water vapor contribution while in the upper troposphere, the two opposite contributions offset each other almost completely. A paper has been drafted based on the above work and findings. Sarah M. Kang, Graduate Student Sarah Kang is a second year graduate student. During the first semester, Kang took several classes that are required for the general exam in next year. In numerical methods class, Kang has done a research about how moisture is advected differently when different advection schemes are applied using shallow water model. Kang was able to capture several realistic characteristics from this simple model. In second semester, Kang investigated the influence of aerosol on precipitation over Sahel. To make a link between aerosol and precipitation, Kang has worked on how aerosol affects the shortwave flux at the surface and how it changes the sea surface temperature over North Atlantic Ocean and Indian Ocean. Throughout the year, Kang has developed an interest in African climate change. The African Sahel experienced a prolonged dry episode in the latter decades of the 20th century. It's surprising that every model produces different trend for the next century. Especially, Japanese model says it'll get moistened and GFDL model says it'll become drier catastrophically. To understand what is going on over Sahel, Kang decided to use an intermediate complexity moist general circulation model to study what determines the extent of precipitation movement, the position of ITCZ and the boundary of rainbelt. Kang started working with a simplified moist GCM. Several experiments, like putting an idealized rectangular continent and inputting seasonal variation by modifying solar flux as a function of time have been done recently. These days Kang has been concentrated on the experiments taking heat out of the southern hemisphere and put it hack to the northern hemisphere to make asymmetry in Hadley cells and figure out how ITCZ moves. Seoung Soo Lee, Graduate Student I am a third-year grad student in AOS program at Princeton University, working with Dr. Leo Donner as my advisor. I have studied the interaction between aerosol and cloud. After industrialization around the world, there has been an increase in aerosol mass and concentration. Anthropogenic aerosols are typically in the submicrometer- to micrometer-size range, suitable range to act as Cloud Condensation Nuclei(CCN) [ Haywood and Boucher, 2000 ], which means human activity can change cloud properties and hence climate. Anthropogenic sources contribute almost as much as natural sources to the global aerosol amount[ Hansen et al. , 1997 ; Robertson et al., 2001]. These newly added aerosols from anthropogenic sources are considered to partially offset global warming by reflecting more incoming solar radiation. This is the aerosol direct effect on climate and leads to uncertainties in predicting climate. But the uncertainties are higher in aerosol indirect effect, because the indirect effect accompanies cloud microphysics. Aerosols can act as CCN, and therefore, the change in aerosol properties, such as number concentration, can change cloud development and a role of clouds in climate. The increase in aerosol number concentration induces a decrease in droplet size, increase in reflected solar radiation (first aerosol indirect effect) and precipitation suppression (second aerosol indirect effect). Ramanathan et al. [2001] pointed out the second indirect effect on precipitation and radiation spin down the hydrologic cycle and increased reflection of solar radiation. But my study shows contrary results to traditional precipitation suppression, indicating the role of aerosol can differ in deep convections. Cynthia A. Randles, Graduate Student Ph.D. Candidate, Atmospheric and Oceanic Sciences Program M. A. Princeton Atmospheric and Oceanic Sciences Program, 2003 S. B. in Earth, Atmospheric & Planetary Sciences, MIT, 2000 CICS Research Theme: Earth System Studies/Climate Research Thesis Topic: Carbonaceous aerosol effects on climate Atmospheric aerosols play several important roles in the climate system. By scattering and absorbing incoming solar radiation, they directly impact the amount of radiation reaching the surface. Indirectly, they can modify the microphysical properties of clouds, increasing cloud brightness and decreasing precipitation. Absorbing aerosol, such as black carbon (BC), dust, and some organic carbon (OC), can have an additional “semi-direct” effect. The semi-direct effect of absorbing aerosol causes a redistribution of warming in the atmosphere as the aerosol layer absorbs incoming solar radiation. This can lead to a warming in clouds that can result in a partial evaporation that reduces the cloud albedo, which in turn warms the surface. Aerosol can exist as an external mixture composed of separate particles of dust, sea salt, OC, BC, and sulfate, or these constituents may be combined in random ways to form an internal mixture. The chemical composition of aerosol, which is a function of mixing state, will determine its refractive index. Along with particle shape and size, the refractive index will dictate the amount of light a particle will scatter and absorb at a given wavelength of light. In addition, the composition of the aerosol will determine its hygroscopicity, or how much water it will take up in a humid atmosphere. Aerosol hygroscopicity can then influence chemical composition and shape, further changing the optical properties of the aerosol. I began my thesis research in 2001 working with V. Ramaswamy of the Princeton AOS program and Lynn M. Russell from Princeton’s Chemical Engineering Department. My research focused on studying the effects of mixing water-soluble organic compounds (WSOC) with sea-salt aerosol, focusing on changes in aerosol hygroscopicity and the resulting changes in optical properties. This research was motivated by the fact that organic compounds may account for up to 50% of marine aerosol mass, and that many WSOC, when mixed with sea-salt aerosol, will reduce water uptake and therefore the scattering ability of aerosol, thus reducing the cooling from sea-salt predicted by climate models which do not include this effect of the WSOC. By analogy, WSOC can also become associated with sulfate particles, which also experience a reduction in hygroscopic growth and scattering when mixed with WSOC. Thus, it is likely that if WSOC are associated with sulfates and sea salt, the global radiative cooling associated with organic compounds is overestimated because of inadequate accounting of their hygroscopic growth and absorption effects, thus making it imperative that evaluations of aerosol climate effects consider these physical processes explicitly. This research culminated in a paper which was published in Geophysical Research Letters in 2004. In the summer of 2004, I was given the opportunity to participate in the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) Chemistry of Halogens at the Isles of Shoals (CHAiOS) field study on Appledore Island, Maine with Lynn Russell. This project augmented the AIRMAP observatory on Appledore Island, 12 km off the coast of New Hampshire, with an extensive suite of aerosol and trace gas measurement systems. Deployed systems for trace gas measurements included long-path and multi-axis DOAS, automated GC-MS, PTR-MS, mist chambers and filter packs. Aerosol systems included an APS, a SMPS, cascade impactors and bulk aerosol filters. I was responsible for the aerosol measurements with the APS, which measures aerosol particles > 1 micron in diameter, and the SMPS, or scanning mobility particle system, which measured aerosol size distributions for aerosol < 1 micron in diameter. In addition, 12-hour aersol bulk filter samples were taken for later analysis at the Scripps Institution of Oceanography (SIO) using a Fourier Transform Infrared Spectrometer (FTIR) to look for organic functional groups. Currently, I am working on studying the effects of black carbon (BC) aerosol over China and India using the Geophysical Fluid Dynamics Laboratory’s (GFDL) AM2 Global Climate Model (GCM). I am looking at the climate effects of increasing aerosol absorption by increasing the fraction of BC versus scattering anthropogenic aerosol (sulfate and organics), and of the effects of increasing the total column burden of absorbing aerosol (BC). In this study, AM2 is being run with fixed sea-surface temperatures (SSTs) and greenhouse gasses (GHGs) so that only the impact of aerosol changes is considered. The purpose is to understand how the model response, particularly surface temperature, clouds, and the hydrologic cycle, is altered with changes in the heating rate of different atmospheric layers. I am currently investigating changes in radiative forcing resulting from increasing the single scattering albedo throughout the atmospheric column and layer-by-layer over China. I am also looking at the effects of biomass burning OC and BC over Southern Africa using a new GFDL model which includes interactive aerosol. Of particular interest will be the sensitivity of radiative forcing and climate response to the vertical profile of the aerosol and to the mixing state of the biomass burning aerosol. The parameter space for these sensitivity studies can be limited by employing measured data. In particular, I will use ground-based remote sensing (AERONET) and satellite (TOMS) measurements to constrain the range of optical depths and single scattering albedo considered. Publications: Randles, C. A., L. M. Russell, and V. Ramaswamy (2004), Hygroscopic and optical properties of organic sea salt aerosol and consequences for climate forcing, Geophys. Res. Lett., 31, L16108, doi:10.1029/2004GL020628. Poster Presentations: Randles, C. A., L. M. Russell, and V. Ramaswamy (2004), Hygroscopic and optical properties of organic sea salt aerosol and consequences for climate forcing, 8th International Global Atmospheric Chemistry (IGAC) Conference, Christchurch, New Zealand. Agnieszka Smith-Mrowiec, Graduate Student Ph.D. Candidate, AOS Department at Princeton University Ph.D. in Geophysics at Warsaw University (October 2001 – August 2002, discontinued) M. Sc. in Physics (2001) at Warsaw University, Poland Hurricanes wreak devastation on costal communities each year, causing loss of life and billions of dollars of damage. Nevertheless, many basic aspects of the dynamics that control the formation and steady state parameters of a hurricane are not understood and hence not predictable. A typical hurricane is nearly axisymmetric, and has an axial wind profile that achieves a maximum at some well-defined distance from its center. This distance is called the Radius of Maximum Wind (RMW), and is one of the most important dynamical parameters necessary to describe any given hurricane. Predicting it would be invaluable when assessing possible disaster range at landfall. Not much is known about what sets the RMW. It is clear, though, that there is no simple correlation between RMW and other obvious dynamical parameters, such as maximum wind speed, minimum central pressure, or environmental conditions such as sea surface temperature. Smith-Mrowiec began her PhD study two years ago, and has been working with Garner and Pauluis to investigate what sets the RMW. This is an ongoing project. The investigation involved the use of an axisymmetric, nonhydrostatic hurricane model (ZETAC). The resolution of the model for the preliminary study was 2.5 km and the domain size was 500 km. Initial simulations were made for 15 days of hurricane life, with the objective of generating a steady state. The preliminary study revealed, however, that even generating a steady state was very challenging. The model was set up to run in both 2D and 3D. 3D is interesting because convective dynamics is altered and also the azimuthal wave instability can be observed. Once the intermediate studies are completed (effects of larger domain size, higher resolution (1 km) and generating a set of self-consistent atmospheric states for each sea surface temperature that would be used), the next step will be to study the correlation of the RMW with a quantity called Maximum Potential Intensity (MPI - see Emanuel, 1988,1995, Holland 1996). Hurricanes derive their energy from the thermodynamic disequilibrium between the tropical oceans and the atmosphere, and the MPI quantitatively summarizes this. Emanuel's maximum potential intensity theory predicts an upper limit for the maximum wind, depending mostly on the sea surface temperature, atmosphere temperature and the efficiency of the heat conversion into wind energy. The Emmanuel theory will be used as a basis from which to approach the underlying dynamics controlling the RMW. References: Emanuel, K. A., 1988: The maximum intensity of hurricanes. J. Atmos. Sci., 45 Emanuel, K. A., 1995: Sensitivity of tropical cyclones to surface exchange coefficients and a revised steady-state model incorporating eye dynamics. J. Atmos. Sci., 52 Holland, G., 1996: The maximum potential intensity of tropical cyclones. J. Atmos. Sci.