Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Sun-Earth System
Document related concepts
Transcript
Our Home in Space: The Sun-Earth System Judith Lean Naval Research Laboratory, Washington DC SATURN JUPITER EARTH SUN AASM, 11APR06 Sun-Earth System – an overview The Sun, a Star, is our energy source The Earth, a planet, is our home Variability in the Space Era – past 30 years Total Irradiance – Climate … where we live UV Irradiance – Ozone … our protective atmosphere EUV Irradiance, particles, plasma – Space Weather … technology Relationships in the Past - last century - last millennium - last 10,000 years –the Holocene …… our current interglacial SUN 5770 K 100,000 K convection zone radiative zone core 4.5 billion years Thermosphere T T deep space 4K Stratosphere EARTH 288 K 1,000 K Troposphere radiated photons reflected photons photons surface surface atmosphere atmosphere 1,391,980 km not to scale 149,597,900 km 1 Astronomical Unit 12,742 km Solar Radiation Establishes the Thermal Structure of the Earth and its Atmosphere Altitude - km wavelengths < 100 nm Thermosphere Ionosphere T Mesosphere Stratosphere wavelengths 100-300 nm Troposphere wavelengths > 300 nm SUN (255 K) + GHG (33 K) = 288 K SUN convection zoe radiative zone core galactic cosmic rays EARTH solar wind particles (mainly protons) and magnetic fields photons bow shock surface atmosphere plasmasphere magnetosphere surface sunspot atmosphere faculae, plage coronal mass ejection heliosphere not to scale mixed layer deep ocean ENERGY FLOW 1.5108 km 0.00065 0.00035 0.05 0.002 0.002 galactic cosmic rays 0.0000007 300-1000 nm plasma wind 414.2 0.0009 0.1 0.45 W m-2 0.0032 14.9 936.3 Cycle Amplitude Earth’s surface energetic particles 1000-10000 nm troposphere 120-300 nm thermosphere/ Ionosphere mesosphere stratosphere electromagnetic radiation 5-120 nm plasmasphere Energy Flux magnetosphere EARTH EARTH SPACE OCEAN ATMOSPHERE ENVIRONMENT HELIOSPHERE chromosphere transition region corona Sun’s surface Wavelength photosphere SOLAR SOLAR ATMOSPHERE INTERIOR core radiative zone convection zone Sun-Earth System – an overview The Sun, a Star, is our energy source The Earth, a planet, is our home Variability in the Space Era – past 30 years Total Irradiance – Climate … where we live UV Irradiance – Ozone … our protective atmosphere EUV Irradiance, particles, plasma – Space Weather … technology Relationships in the Past - last century - last millennium - last 10,000 years –the Holocene …… our current interglacial 12DEC96 The Sun’s Activity Drives the Sun-Earth System Heliosphere SOHO/MDI 29 Mar 2001 sunspots have an 11-year cycle 21 22 16JAN03 31JAN03 LASCO 23 Corona EIT Chromosphere-TR KPNO magnetic flux Photosphere Surface Magnetic Field MDI SOHO The Solar “Constant” Varies! data: Fröhlich & Lean,AARev,2004 http://www.pmodwrc.ch cycle 21 cycle 22 cycle 23 Total Solar Irradiance: 5-min oscillation ~ 0.003% 27-day solar rotation ~ 0.2% 11-year solar cycle ~ 0.1% longer-term variations not yet detectable – ……do they occur? Past Solar Activity sunspot cycle amplitudes have increased from the Maunder Minimum … to the Modern Maximum SOHO: 1996 ACRIMSAT: 1999 SORCE: 2003 http://lasp.colorado.edu/sorce/ Sources of Solar Irradiance Variations: 17 OCT 03 - dark sunspots - bright faculae 30 OCT 03 2 AUG 6 AUG sunspots dominate faculae during solar rotation solar photosphere faculae dominate sunspots during solar cycle 16 JUN 96 25 FEB 02 near UV,VIS,IR radiation 1366 Wm-2 climate Causes of Recent Climate Change Anthropogenic Forcings • atmospheric GH gases - CO2, CH4, CFCs, O3, N2O • tropospheric aerosols - direct and indirect effects of soot, sulfate, carbon, biomass burning, soil dust Land Cover Changes Internal Oscillations • atmosphere-ocean couplings - El Niño Southern Oscillation (ENSO) - North Atlantic Oscillation (NAO) Natural Forcings • solar variability - direct and indirect effects • volcanic eruptions - stratospheric aerosols • Climate Change Science, “An Analysis of Some Key Questions”, National Research Council, 2001 • IPCC, 1992, 1995, 2001 Solar and Anthropogenic Climate Signals GISS Land+Ocean Global Temperature monthly means El Nino La Nina volcanic aerosols http://data.giss.nasa.gov/ greenhouse gases industrial aerosols Climate Response to Radiative Forcing water vapor forcing FEEDBACKS surface temperature change ΔT = F climate sensitivity IPCC range: 0.2-1oC per Wm-2 paleoclimate: 0.75oC per Wm-2 http://visibleearth.nasa.gov Hansen, 2004 mixed layer BUT…. response to cyclic decadal forcing is assumed to be attenuated by 5 compared with “equilibrium” response cloud cover http://www.hpl.umces.edu/~lzhong/mixed_layer/sml.htm Solar Irradiance Cycle ΔT = 0.1oC F = 0.15 Wm-2 (0.850.7/4) = 0.67oC per Wm-2 sea-ice/ snow cover Solar Cycle Signals in Earth’s Atmosphere MIDDLE TROPOSPHERE 8 km Temperature Anomaly (K) SURFACE 0 km solar increase warming CO2 increase warming volcanoes cooling LOWER STRATOSPHERE 20 km El Nino El Chichon Pinatubo La Nina solar increase warming CO2 & CFC increase cooling volcanoes warming UV radiation (λ < 315 nm) Sun Sun, Stratosphere, Ozone 20 Wm-2 O2 photodissociation O3 production O3 destruction unit optical depth near UV,VIS,IR Radiation (λ > 315 nm) 1346 Wm-2 Stratosphere The Ozone Layer: Recent Variations 4% Total Ozone 50S-50N ~ 280 DU GSFC TOMS Total Ozone Sep 16, 2001 1996-06-16 +1.2% UV radiation: 200-295 nm Nimbus 7 Pittock (1978): Sun-ozone correlations … “experiments in autosuggestion” solar upper photosphere/ 2000-02-25 chromosphere EP/TOMS Total Ozone Sep 16, 2001 2.2% Stratosphere – Climate Coupling Dynamical Coupling via Wind-Wave Interactions Radiative Forcing Sensitivity Lower Middle Atmosphere Atmosphere Radiative Coupling via Absorption and Emission Change Ozone & Temperature Change Winds & Planetary Waves Change Temperature Advection &Temperature Change Winds & Planetary Waves Change Climate Shindell et al., 2003; Rind et al., 2004 Lacis et al., 1979 NORTH ATLANTIC OSCILLATION • solar irradiance cycle modulates stratospheric polar vortex • tropospheric circulation • NAO (solar min) AO (solar max) Kodera, 2003 Positive NAO Negative NAO solar min max SPACE Sun = 400K WEATHER solar increase warming GHG = -3K CO2 increase cooling Thermosphere Ionosphere solar EUV radiation λ< 100 nm Altitude T TOMS UV radiation exposure: January Stratosphere Troposphere solar min max Sun = +0.3K GHG = -0.4K solar increase warming CO2 increase cooling ozone depletion climate change GLOBAL CHANGE solar increase warming CO2 increase warming solar min max Sun = +0.1K GHG = +0.2K Sun and Thermosphere-Ionosphere solar EUV photon energy 100% quiet Sun response to EUV photons response to particles, plasma, fields solar wind kinetic energy (~protons) 500 km temperature 16 JAN 03 neutral density spacecraft drag corona electron density chromosphere heliosphere communication, navigation July 1979 solar EUV irradiance changes modulate upper atmospheric densities, affecting the orbits of >10,000 resident space objects Spacecraft Drag EUV Irradiance 1999 International Space Station: 400 km YOHKOH Altitude Density at YOHKOH Yohkoh: Space Command Radar Fence launched 30 AUG 1991 Re-entered 12 SEPT 2005 surface SOHO/EIT 171 20031028 13:00 “Halloween” Solar Storm chromosphere-TR October 28th, 2003 active region with big sunspot erupts …. 8 minutes later ... X-class flare recorded by GOES EIT 304 20031028 13:19 coronal mass ejection leaves the Sun …. 8 hours later... particles saturate SOHO/LASCO detector and reach Earth SOHO/LASCO 20031028 12:42 X-ray photons NOAA National Weather Service http://www.sec.noaa.gov/ 30 Rsun heliosphere … at L1 20031028 20:49 energetic protons Solar Variability Drives Space Weather solar photons & solar and magnetospheric particles heat and ionize Earth’s atmosphere and ionosphere aurora spacecraft drag, collisions, loss communications & navigation currents induced in power grids hazards to humans in space spacecraft detector upsets www.nas.edu.ssb/cover.html March 1989: Auroral Oval Power System Events Sun-Earth System – an overview The Sun, a Star, is our energy source The Earth, a planet, is our home Variability in the Space Era – past 30 years Total Irradiance – Climate … where we live UV Irradiance – Ozone … our protective atmosphere EUV Irradiance, particles, plasma – Space Weather … technology Relationships in the Past - last century - last millennium - last 10,000 years – the Holocene …. our current interglacial In early September in 1859, telegraph wires suddenly shorted out in the United States and Europe, igniting widespread fires. Colorful aurora, normally visible only in polar regions, were seen as far south as Rome and Hawaii. Sun and Climate in Recent Centuries 1613 Galileo 1995 SOHO sunspot cycle amplitudes have increased from the Maunder Minimum to the Modern Maximum 1960-2000 Earth’s surface temperature has increased in the last century.. changes are non-uniform, globally and temporally http://giss/nasa/gov 1900-1950 3 2.4 2 1 CO2 0.35 0.25 halocarbons N2 O CH4 tropospheric ozone fossil fuel burning 0 -1 stratospheric ozone -2 0.2 0.1 0.3 mineral aviation dust contrails & cirrus biomass burning sulphate 0.4 0.05 indirect aerosol 0.25 (FSUN=ΔS0.7/4) solar landuse (albedo) 0.23 -3 solar forcing Pre-Industrial Solar Forcing F = 0.3 Wm-2 ΔT = 0.2oC = 0.6oC per Wm-2 volcanic forcing anthropogenic & solar forcing (Bradley & Jones, 1993) Tamboora Coseguina Krakatoa Lean et al., 1995 cooling warming Radiative Forcing (Wm-2) 1750-2000 Industrial-Era Climate Forcing: IPCC 2001 Climate Change in Recent Centuries forcings GCM simulation: ~ 4oC for 2×CO2 Robinson et al., 2001 EBM simulation: ~ 2oC for 2×CO2 Crowley, 2000 omitting solar forcing .. poorer tracking of centennial variations .. higher sensitivity to GHGs Holocene Sun-Climate Connections INTERTROPICAL CONVERGENCE ZONE 18O in stalagmites in Oman track 14C for 3,000 years in mid-Holocene Neff et al., Nature, 2001 NORTH ATLANTIC CLIMATE surface winds and ocean hydrography affected by solar variability -North Atlantic Deep Water may amplify solar signals Bond et al., Science, 2001 high solar activity low 14C low 18O high rainfall high solar activity low 14C less drift ice southward Centennial-Millennial Solar Variability cosmogenic isotope changes - 14C in tree-rings, 10Be in icecores imply long-term solar activity … do they also imply long-term solar irradiance variations? 0.1% chromosphere corona photosphere Mechanisms of Cosmogenic Isotope and Solar Irradiance Variability EIT284 EIT304 open flux in coronal holes – extends to heliosphere open flux modulates cosmogenic isotopes Radial Interplanetary Magnetic Field closed flux in active regions and network MDI surface magnetic fields of opposite polarity 24 June 2002 closed flux modulates irradiance Irradiance at Earth 1365 Wm-2 Galactic Cosmic Ray Flux at Earth 0.0000007 Wm-2 Evolution of the Sun’s Surface Magnetic Field Drives Long-Term Solar Irradiance Changes magnetogram magnetic flux is transported by…. surface magnetic fields of opposite polarity differential rotation poleward meridional flow diffusion Long-Term Solar Irradiance Simulated by a Flux Transport Model sub-surface dynamo 0.08% 0.2% www.hao.ucar.edu, Y.-M. Wang, N. Sheeley science.nasa.gov/ssl/pad/solar Causes of Climate Change in the Recent Past 0.9K 0.1K Radiative Forcing 1750-2000 0.7K IPCC 2001: (Wm-2) Greenhouse Gases +2.4 Ozone +0.15 +0.12 Solar +0.3 Landuse -0.23 Tropospheric -0.4 to -1.4 Aerosols Hansen et al., 2001 Tropospheric Aerosols -0.6 Empirical Reconstruction Sun-Earth System: Emerging Questions Long-term solar variability and terrestrial responses - solar dynamo action, irradiance and heliospheric modulation, terrestrial responses Eruptive energy outputs and terrestrial responses - flare spectra, relative impacts of flares and CMEs, time scales of terrestrial responses Solar-driven versus other influences on Earth - volcanic influences, internal modes (ENSO, NAO, QBO), geenhouse gases Vertical couplings of solar and other influences -radiative and dynamical up & down atmospheric couplings - surface to themosphere -radiative and plasma couplings of thermo/ionsophere and plasma/megnetosphere Non-linear system responses -mode amplification (ENSO), stochastic resonance, frequency modulation, triggering altered stability states Ability of models to simulate system responses -mechanisms, data assimilation, subsystem interfaces, transition to operations In seeking answers to such questions oncedisparate fields are coalescing slowly and a new paradigm is emerging – … of the Sun and Earth as one unified system, our home in space that extends well beyond the surface where we live. Physics Today, June 2005: “Living with a Variable Sun” Communication, Navigation Bastille Day 2000 solar eruption flares active region evolution solar cycle X-ray and EUV irradiance variation ionospheric electron density response Yohkoh SXT NRL SAMI2 model (Huber and Joyce) Meier et al., 2000 nemax=1.24×104fo2 reflection, refraction time delays, phase shifts fades, polarization rotation • disrupts communications • degrades radar accuracy et al., GRL, 2001 • disrupts/degrades Meier navigation • degrades precision targeting Sun – Climate - Ozone: Future Decadal Variability Radiative Forcing Total Ozone solar cycle Total Solar Irradiance Monitoring SORCE GLORY NPOESS ?? C. Jackman, GSFC Sun’s role in future climate change depends on irradiance cycles and trends relative to anthropogenic scenarios Coronal Mass Ejections Propagate to Earth through the Heliosphere … hours to days Coronal Mass Ejection SOHO/LASCO 1997-11-06 103 cm-1 sec-1 str-1 Particle Transport Particle-Plasma Wave Interactions solar magnetic cloud perturbs Earth’s magnetic field lines affects energetic particle penetration of Earth’s atmosphere
