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EARTH

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.

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EARTH

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  1. Our Home in Space: The Sun-Earth System Judith Lean Naval Research Laboratory, Washington DC SATURN JUPITER EARTH SUN AASM, 11APR06

  2. 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

  3. SUN EARTH  4.5 billion years Thermosphere  5770 K 288 K T T 100,000 K 1,000 K Stratosphere deep space 4K convection zone radiative zone Troposphere core radiated photons radiated photons reflected photons reflected photons photons photons surface surface atmosphere atmosphere 149,597,900 km 1 Astronomical Unit 1,391,980 km 12,742 km not to scale

  4. Solar Radiation Establishes the Thermal Structure of the Earth and its Atmosphere wavelengths < 100 nm Thermosphere Ionosphere  T Mesosphere Altitude - km wavelengths 100-300 nm Stratosphere Troposphere wavelengths > 300 nm SUN (255 K) + GHG (33 K) = 288 K

  5. SUN EARTH galactic cosmic rays convection zoe radiative zone core solar wind particles (mainly protons) and magnetic fields photons bow shock surface surface sunspot atmosphere atmosphere faculae, plage plasmasphere coronal mass ejection magnetosphere heliosphere not to scale

  6. core radiative zone convection zone SOLAR INTERIOR electromagnetic radiation Sun’s surface photosphere chromosphere transition region corona energetic particles SOLAR ATMOSPHERE W m-2 plasma wind 0.0032 0.0009 Energy Flux Cycle Amplitude HELIOSPHERE 936.3 0.45 14.9 0.1 414.2 0.05 0.00065 0.00035 0.002 0.002 1.5108 km magnetosphere plasmasphere EARTH SPACE ENVIRONMENT 5-120 nm 120-300 nm galactic cosmic rays thermosphere/ Ionosphere mesosphere stratosphere troposphere Wavelength 300-1000 nm 1000-10000 nm EARTH ATMOSPHERE 0.0000007 Earth’s surface mixed layer deep ocean ENERGY FLOW OCEAN

  7. 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

  8. 12DEC96 16JAN03 31JAN03 The Sun’s Activity Drives the Sun-Earth System SOHO/MDI 29 Mar 2001 LASCO Heliosphere sunspots have an 11-year cycle 23 21 22 Corona EIT Chromosphere-TR KPNO magnetic flux MDI Photosphere SOHO Surface Magnetic Field

  9. 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 SOHO: 1996  ACRIMSAT: 1999  SORCE: 2003  sunspot cycle amplitudes have increased from the Maunder Minimum … to the Modern Maximum http://lasp.colorado.edu/sorce/

  10. Sources of Solar Irradiance Variations: 17 OCT 03 30 OCT 03 - dark sunspots 2 AUG 6 AUG - bright faculae sunspots dominate faculae during solar rotation solar photosphere faculae dominate sunspots during solar cycle near UV,VIS,IR radiation 1366 Wm-2 climate 16 JUN 96 25 FEB 02

  11. 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

  12. 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

  13. Climate Response to Radiative Forcing water vapor surface temperature change forcing ΔT =F FEEDBACKS sea-ice/ snow cover climate sensitivity IPCC range: 0.2-1oC per Wm-2 paleoclimate: 0.75oC per Wm-2 Hansen, 2004 http://visibleearth.nasa.gov http://www.hpl.umces.edu/~lzhong/mixed_layer/sml.htm cloud cover Solar IrradianceCycle ΔT = 0.1oC F = 0.15 Wm-2(0.850.7/4)  = 0.67oC per Wm-2 mixed layer BUT…. response to cyclic decadal forcing is assumed to be attenuated by  5 compared with “equilibrium” response

  14. Solar Cycle Signals in Earth’s Atmosphere MIDDLE TROPOSPHERE LOWER STRATOSPHERE SURFACE 0 km 8 km 20 km  Temperature Anomaly (K) El Nino El Chichon Pinatubo La Nina solar increase warming CO2 increase warming volcanoes cooling solar increase warming CO2 & CFC increase cooling volcanoes warming

  15. UV radiation (λ < 315 nm) 20 Wm-2 Sun, Stratosphere, Ozone Sun O2 photodissociation O3 production O3 destruction unit optical depth near UV,VIS,IR Radiation (λ > 315 nm) 1346 Wm-2 Stratosphere

  16. The Ozone Layer: Recent Variations 1996-06-16 UV radiation: 200-295 nm +1.2% solar upper photosphere/ chromosphere 2000-02-25 4% Total Ozone 50S-50N ~ 280 DU EP/TOMS Total Ozone Sep 16, 2001 2.2% GSFC TOMS Total Ozone Sep 16, 2001   Nimbus 7  Pittock (1978): Sun-ozone correlations … “experiments in autosuggestion”

  17. Change Ozone & Temperature Middle Atmosphere Change Winds & Planetary Waves Change Temperature Advection &Temperature Lower Atmosphere Change Winds & Planetary Waves Change Climate Stratosphere – Climate Coupling Dynamical Coupling via Wind-Wave Interactions Radiative Coupling via Absorption and Emission Radiative Forcing Sensitivity 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

  18. solar min max Sun = 400K GHG = -3K SPACE WEATHER solar increase warming CO2 increase cooling Thermosphere Ionosphere solar EUV radiation λ< 100 nm  solar min max Sun = +0.3K GHG = -0.4K T TOMS UV radiation exposure: January solar increase warming CO2 increase cooling Stratosphere Altitude ozone depletion GLOBAL CHANGE climate change Troposphere solar increase warming CO2 increase warming solar min max Sun = +0.1K GHG = +0.2K

  19. Sun and Thermosphere-Ionosphere 500 km solar EUV photon energy quiet Sun 100%  response to EUV photons  response to particles, plasma, fields temperature solar wind kinetic energy (~protons) 16 JAN 03 neutral density spacecraft drag corona communication, navigation electron density chromosphere heliosphere

  20. July 1979 Spacecraft Drag solar EUV irradiance changes modulate upper atmospheric densities, affecting the orbits of >10,000 resident space objects EUV Irradiance 1999 International Space Station: 400 km YOHKOH Altitude Density at YOHKOH Yohkoh: launched 30 AUG 1991 Re-entered 12 SEPT 2005 Space Command Radar Fence

  21. SOHO/EIT 171 20031028 13:00 “Halloween” Solar Storm October 28th, 2003 surface chromosphere-TR active region with big sunspot erupts …. EIT 304 20031028 13:19 8 minutes later ... X-class flare recorded by GOES X-ray photons coronal mass ejection leaves the Sun …. NOAA National Weather Service http://www.sec.noaa.gov/ 8 hours later... particles saturate SOHO/LASCO detector and reach Earth SOHO/LASCO 20031028 12:42 30 Rsun heliosphere energetic protons … at L1 20031028 20:49

  22. Solar Variability Drives Space Weather • solar photons & solar and magnetospheric particles • heat and ionize Earth’s atmosphere and ionosphere March 1989: Auroral Oval • aurora Power System Events • 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

  23. 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 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. Relationships in the Past - last century - last millennium - last 10,000 years – the Holocene …. our current interglacial

  24. 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.. 1900-1950 changes are non-uniform, globally and temporally http://giss/nasa/gov

  25. Industrial-Era Climate Forcing: IPCC 2001 CO2 3 2 1 0 -1 -2 -3 2.4 0.35 0.25 0.05 0.3 halocarbons warming (FSUN=ΔS0.7/4) N2O fossil fuel burning aviation contrails & cirrus CH4 mineral dust tropospheric ozone solar 1750-2000 Radiative Forcing (Wm-2) landuse (albedo) biomass burning stratospheric ozone sulphate cooling indirect aerosol 0.2 0.4 0.1 0.25 0.23 solar forcing volcanic forcing anthropogenic & solar forcing (Bradley & Jones, 1993) Pre-Industrial Solar Forcing F = 0.3 Wm-2 ΔT = 0.2oC  = 0.6oC per Wm-2 Tamboora Coseguina Krakatoa Lean et al., 1995

  26. 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

  27. 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 high solar activity low 14C low 18O high rainfall high solar activity low 14C less drift ice southward 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

  28. 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%

  29. Mechanisms of Cosmogenic Isotope and Solar Irradiance Variability corona open flux in coronal holes – extends to helio-sphere open flux modulates cosmogenic isotopes closed flux modulates irradiance EIT284 Radial Interplanetary Magnetic Field chromosphere closed flux in active regions and network EIT304 photosphere Irradiance at Earth 1365 Wm-2 MDI surface magnetic fields of opposite polarity Galactic Cosmic Ray Flux at Earth 0.0000007Wm-2 24 June 2002

  30. Evolution of the Sun’s Surface Magnetic Field Drives Long-Term Solar Irradiance Changes magnetogram magnetic flux is transported by…. poleward meridional flow differential rotation diffusion Long-Term Solar Irradiance Simulated by a Flux Transport Model surface magnetic fields of opposite polarity sub-surface dynamo 0.08% 0.2% www.hao.ucar.edu, Y.-M. Wang, N. Sheeley science.nasa.gov/ssl/pad/solar

  31. 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 Solar +0.3 Landuse -0.23 Tropospheric -0.4 to -1.4 Aerosols Hansen et al., 2001 Tropospheric -0.6 Aerosols +0.12 Empirical Reconstruction

  32. 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

  33. In seeking answers to such questions once-disparate 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”

  34. 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 reflection, refraction time delays, phase shifts fades, polarization rotation nemax=1.24×104fo2 • disrupts communications • degrades radar accuracy • disrupts/degrades navigation • degrades precision targeting Meier et al., GRL, 2001

  35. Sun – Climate - Ozone: Future Decadal Variability Radiative Forcing Total Ozone IPCC, 1995 Hansen et al, 2000 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

  36. Coronal Mass Ejections Propagate to Earth through the Heliosphere … hours to days Coronal Mass Ejection SOHO/LASCO 1997-11-06 • solar magnetic cloud perturbs Earth’s magnetic field lines Particle Transport Particle-Plasma Wave Interactions • affects energetic particle penetration of Earth’s atmosphere 103 cm-1 sec-1 str-1

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