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Sensor Webs in Digital Earth: Monitoring Climate Change Impacts Matt Heavner (Univ Alaska Southeast, Juneau, Alaska) Rob Fatland (Vexcel/Microsoft Geospatial Solutions, Boulder, Colorado) Eran Hood, Cathy Connor (Univ Alaska Southeast, Juneau, Alaska) Tracy Lee Hansen, Mary Sue Schultz, Tom LeFavre (NOAA Earth System Research Lab, Boulder, Colorado) Albert Esterline (NCA&T, Greensboro, North Carolina) ABSTRACT: The University of Alaska Southeast is currently implementing a sensor web identified as the SouthEast Alaska MOnitoring Network for Science, Telecommunications, Education, and Research (SEAMONSTER). From power systems and instrumentation through data management, visualization, education, and public outreach, SEAMONSTER is designed with modularity in mind. We are utilizing virtual earth infrastructures to enhance both sensor web management and data access. We will describe how the design philosophy of using open, modular components contributes to the exploration of different virtual earth environments. We will also describe the sensor web physical implementation and how the many components have corresponding virtual earth representations. This presentation will provide an example of the integration of sensor webs into a digital earth. We suggest that sensor networks and sensor webs should integrate into digital earth systems and provide a resource easily accessible to both scientists and the public. The initial scientific application of the SEAMONSTER sensor web is to monitor climate change impacts of glaciated watersheds in Southeast Alaska. Melting glaciers are dominating the biogeochemistry of watersheds and as the glaciers disappear, this influence will diminish. By monitoring these watersheds using a sensor web, we are improving knowledge regarding impacts of climate change. INTRODUCTION Impacts of climate change are especially pronounced in the polar regions of the planet (ACIA, 2005). Because these areas are less accessible to the majority of the population, the regions are historically less well studied. Additionally, public awareness of the impacts of climate change in the polar-regions is often lacking. One important aspect of climate change impacts is on the cryosphere, or frozen water regions of the world. By understanding the changes of glaciers in more equatorial regions of the poles, we provide insight into the potential responses of the large masses of ice (e.g. Greenland, Antarctica) Deploying a large number of sensors or utilizing satellite remote sensing is the present technology for environmental remote sensing over a large geographical region. NASA and other groups are exploring the concept of a sensor web. A NASA Earth Science Technology Office Advanced Information Systems Technology workshop on Sensor Webs developed the definition: “A sensor web is a coherent set of heterogeneous, loosely-coupled, distributed nodes, interconnected by a communications fabric that can collectively behave as a single dynamically adaptive and reconfigurable observing system. The Nodes in a sensor web interoperate with common standards and services. Sensor webs can be layered or linked together.” (AIST, 2007) The critical difference between a sensor web and a sensor network is the communication and semi-autonomous operation (and reconfiguration) of the heterogenous nodes. We report on the SEAMONSTER project which implements sensor web technology in Southeast Alaska and provides a specific example of the difference between a sensor network and a sensor web. The communication and reconfiguration aspects of a sensor web are described in more detail by AIST (2007) and Delin (2005). The University of Alaska Southeast campuses are located within the diverse ecosystems of Juneau, Sitka, and Ketchikan. The campuses are contained within the 17 million acre Tongass National Forest, they border the Juneau Icefield that contains 38 major glaciers covering 1,500 square miles, and a glacial fjord system containing thousands of islands. The South East Alaska MOnitoring Network for Science, Telecommunications, Education, and Research (SEAMONSTER) is a NASA-sponsored smart sensor web project designed to support collaborative environmental science with near-real-time recovery of large volumes of environmental data. Southeastern Alaska is a challenging research environment because of access issues. Due to the mountainous terrain and the island nature of southeast Alaska, access to research sites is unpredictable and expensive and often a primary constraint to research. As a result, the development of a smart sensor web in southeast Alaska will be of tremendous benefit to ongoing earth science and ecological research by UAS and state and federal agency researchers. The UAS campus has access to diverse environments with both inter-tidal ocean and glaciers within 10 kilometers of campus. The initial geographic focus is the Lemon Creek watershed near Juneau Alaska with expansion planned for subsequent years up into the Juneau Icefield and into the coastal marine environment of the Alexander Archipelago and the Tongass National Forest. The overarching concept of SEAMONSTER is that the first generation of sensor web technologies currently exist. SEAMONSTER is an implementation of those technologies intended to act as an educational tool, a public resource, a scientific resource, and a sensor web testbed. The Lemon Creek watershed illustrated in the adjacent Figure is accessible from Juneau while offering the extreme conditions found in Southeast Alaska. Microsensor clusters (motes) are indicated as red dots and Microserver (more capable computer) nodes are orange triangles in this example installation. The Lemon Creek watershed is relatively compact (~31 square kilometers) and begins on Lemon Glacier with two supra-glacial lakes at its head. These lakes have periodic outburst drainages that enter Lemon Creek proper via subglacial drainage channels. Below this glacier Lemon Creek flows through steep wilderness terrain, fed by several tributaries, before reaching a region of active mining and industrially zoned use, finally flowing past residential housing in Juneau and emptying into the ocean. UAS has been involved in monitoring the outburst activity of supra-glacial lakes using in-situ pressure transducers with data-loggers. Instrumentation of the lakes, the Lemon Glacier surface (to study any glacial surge or reaction to lake drainages, via geophones and GPS observations), and throughout the watershed provide water quality monitoring, meteorological parameter monitoring (for autonomous prediction of possible drainage events and the resultant change in sensor-web state for enhanced data acquisition), and hazard monitoring. The Lemon Creek watershed is be instrumented via a sensor web to monitor turbidity, flow, temperature, and meteorological parameters. The catastrophic drainage of the lakes and the resulting impact on the watershed is a transient event that requires sensor web technology to provide autonomous adaptation to current environmental conditions to correctly observe the impacts of the lake drainage on the Lemon creek Watershed. The sensor platforms of SEAMONSTER operate via battery banks and solar panel recharging. The power constraint limits the sampling frequency and operation time of the computers on the sensors. Therefore long sleep cycles are required for power consumption. When a sudden lake drainage is detected (either by a sudden drop in the pressure transducer readings in the lake, or a drastic change in the water temperature at the terminus of the glacier), all platforms can receive the alert signal and increase the sample rate to observe the lake drainage and associated watershed impacts. A second SEAMONSTER study site is the Mendenhall Glacier. Changes in glacier volume and extent are key indicators of climate change. The Mendenhall Glacier is located 10 km northeast of the UAS campus. SEAMONSTER is used to monitor the mass balance (and retreat) of Mendenhall Glacier in partnership with the US Forest Service. The maintenance of a consistent mass balance program on the Mendenhall will help fill an approximately 3,000 km gap in glacier monitoring along the Pacific Coast of North America. The observations are communicated to the public using digital earth technologies to increase public access. Digital Earth is a phrase to describe the virtual 3-D representation of Earth that is spatially referenced and hyperlinked. Examples include Google Earth, Microsoft Virtual Earth, NASA Worldwind, and ESRI’s ArcGIS framework. The digital earth technologies are presently rapidly evolving. Standards efforts by the Open Geospatial Consortium are being implemented for the SEAMONSTER sensor web. This leverages the increasingly available digital earth technology for sensor web management, data analysis, and education and public outreach. Using Digital Earth technology, scientific and public access to SEAMONSTER observations of climate change is increased. Shown above is the retreat of the Mendenhall Glacier during the 2007 summer. This information is given to the US Forest Service Mendenhall Glacier Visitors Center and shared with the approximately 300,000 visitors. By sharing this information via the Internet, even more of the public can be made aware of these observations. A second example of the use of digital earth and sensor webs is the display of water quality parameters in Google Earth via kml. In the Lemon Creek Watershed, this plot shows water temperature by color (4.5-9.0 C, seen in legend on left). One can explore the drainage and see that the main channel is cooler (light blue) and dominated by glacial melt. The non-glacial tributaries (orange, red, yellow) are warmer before they join the main channel. Additional education and public outreach activities include involving K-12 teachers participating in the NSF funded EDGE program (above) in understanding sensor web applications for glacier research. Each teacher participating sends two K-12 students to a summer UAS workshop. The students and teachers are able to maintain involvement with the SEAMONSTER project through the digital earth files we distribute. Finally, Lemon Glacier was studied as part of the 1957-58 International Geophysical Year. Lemon Glacier studies during the 2007-8 International Polar Year are creating a legacy of next generations scientists prepared for sensor web use. ACKNOWLEDGMENTS Funding for SEAMONSTER is provided through NASA Earth Science Technology Office grant AIST-05-0105, NOAA Education Partnership Panel Interdisciplinary Scientific Environmental Technology (ISET) Cooperative Science Center Grant, and NSF Research Experience for Undergraduates Grant No. 0553000. Logan Berner, Marijke Habermann, Erica Halford, Josh Jones, Edwin Knuth, Nick Korzen, Holly Moeller, David Sauer, Shannon Siefert, Suzie Teerlink, Larry Brewster and James Miller have provided SEAMONSTER support. CONCLUSIONS Sensor webs represent the next technological step in environmental monitoring of both long-term climate trends and transient events. Incorporating sensor web and digital earth technologies improves scientific studies, educational efforts, and public outreach all associated with climate change. REFERENCES Arctic Climate Impact Assessment Scientific Report (ACIA), 2005, Cambridge University Press. Report from the Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) Sensor Web Technology Meeting, February 13-14, 2007 http://esto.nasa.gov/sensorwebmeeting/files/AIST_Sensor_Web_Meeting_Report_2007.pdf Delin, K.A. (2004). Sensor Webs in the Wild. In: N. Bulusu and S. Jha (eds.), “Wireless Sensor Networks: A Systems Perspective,”, Artech House.