EARTHEARTH
SUNSUN
JUPITER
SATURN
Our Home in Space: Our Home in Space: The Sun-Earth SystemThe Sun-Earth System
Judith LeanNaval Research Laboratory, Washington DC
AASM, 11APR06
Variability in the Space Era – Variability in the Space Era – past 30 yearspast 30 years Total Irradiance – Climate … where we live UV Irradiance – Ozone … our protective atmosphere EUV Irradiance, particles, plasma – Space Weather … technology
Sun-Earth System – Sun-Earth System – an overviewan overview The Sun, a Star, is our energy source The Earth, a planet, is our home
Relationships in the PastRelationships in the Past - last century - last millennium - last 10,000 years –the Holocene …… our current interglacial
radiated photons
photons
radiative zonecore
convection zone
surfaceatmosphere
4.5 billion years
surface
SUN EARTH
photons
not to scale
1,391,980 km 12,742 km149,597,900 km1 Astronomical Unit
5770 K 288 K
atmosphere
Troposphere
Stratospheredeep space 4K100,000 K 1,000 K
reflected photonsreflected photonsradiated photons
T T
Thermosphere
StratosphereStratosphere
TroposphereTroposphere
MesosphereMesosphere
ThermosphereThermosphereIonosphereIonosphere
SUN (255 K) + GHG (33 K) = 288 K
wavelengths 100-300 nm
wavelengths < 100 nm
Alt
itu
de
- km
wavelengths > 300 nm
Solar Radiation Establishes the Thermal Solar Radiation Establishes the Thermal Structure of the Earth and its AtmosphereStructure of the Earth and its Atmosphere
T
surface
particles (mainly protons)
and magnetic fields
SUN EARTH
photons
core
convection zoeradiative zone
surface atmosphere
magnetosphere
sunspotfaculae, plage
coronal mass ejection
bow shock
plasmasphere
not to scale
solar wind
heliosphere
atmosphere
galactic cosmic rays
coreradiative zoneconvection zone
photosphere
chromospheretransition regioncorona
magnetosphere
plasmasphere
thermosphere/Ionospheremesospherestratosphere
troposphere
mixed layer
deep ocean
Sun’s surface
Earth’s surface
OC
EAN
EAR
TH
ATM
OSP
HER
EEA
RTH
SPA
CE
ENVI
RO
NM
ENT
SOLA
R
ATM
OSP
HER
ESO
LAR
INTE
RIO
RH
ELIO
SPH
ERE
HEL
IOSP
HER
E
5-12
0 nm
120-
300
nm
1000
-100
00 n
m
0.00
32
0.00
09
14.9
0.1
414.
2
0.
05
0.00
065
0.
000
35
electromagnetic radiation
energetic particles
plasma wind
300-
1000
nm
936.
3
0.
45
ENERGY FLOWENERGY FLOW
W m
-2
1.5
108
km
0.00
000
07
galactic cosmic rays
0.00
2
0.00
2
Ener
gy F
lux
Cycle
Am
plitu
deEn
ergy
Flu
x
Cy
cle A
mpl
itude
Wav
elen
gth
Wav
elen
gth
Variability in the Space Era – Variability in the Space Era – past 30 yearspast 30 years Total Irradiance – Climate … where we live UV Irradiance – Ozone … our protective atmosphere EUV Irradiance, particles, plasma – Space Weather … technology
Relationships in the PastRelationships in the Past - last century - last millennium - last 10,000 years –the Holocene …… our current interglacial
Sun-Earth System – Sun-Earth System – an overviewan overview The Sun, a Star, is our energy source The Earth, a planet, is our home
Heliosphere
Corona
Chromosphere-TR
KPNO magnetic flux
12DEC96
Surface Magnetic Field
31JAN0316JAN03
PhotosphereMDI
EIT
LASCO
The Sun’s Activity Drives The Sun’s Activity Drives the Sun-Earth Systemthe Sun-Earth System
sunspots have an 11-year cycle
232221
SOHO/MDI29 Mar 2001
SOHO
sunspot cycle amplitudes have increased from the Maunder Minimum … to the Modern Maximum
SOHO: 1996 ACRIMSAT: 1999 SORCE: 2003
The Solar “Constant” The Solar “Constant” Varies! Varies!
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?
cycle 21 cycle 23data: Fröhlich & Lean,AARev,2004 http://www.pmodwrc.ch
Past Solar Activity
cycle 22
Total Solar Irradiance:Total Solar Irradiance:
http://lasp.colorado.edu/sorce/
- dark sunspots 2 AUG 6 AUG
solar photosphere
near UV,VIS,IR radiation
climate
1366 Wm1366 Wm-2-2
Sources of Solar Sources of Solar Irradiance Variations:Irradiance Variations:
- bright faculae
faculae dominate sunspots during solar cycle
sunspots dominate faculae during solar rotation
17 OCT 0317 OCT 03 30 OCT 0330 OCT 03
25 FEB 0225 FEB 0216 JUN 9616 JUN 96
Anthropogenic Forcings• atmospheric GH gases - CO2, CH4, CFCs, O3, N2O• tropospheric aerosols - direct and indirect effects of soot, sulfate, carbon, biomass burning, soil dust
• Climate Change Science,“An Analysis of Some Key Questions”, National Research Council, 2001• IPCC, 1992, 1995, 2001Natural Forcings
• solar variability - direct and indirect effects• volcanic eruptions - stratospheric aerosols
Internal Oscillations• atmosphere-ocean couplings - El Niño Southern Oscillation (ENSO) - North Atlantic Oscillation (NAO)
Causes of Recent Climate ChangeCauses of Recent Climate Change
Land Cover Changes
Solar and Anthropogenic Climate SignalsSolar and Anthropogenic Climate Signals
greenhouse gasesindustrial aerosols
volcanic aerosols
monthly means
El NinoLa Nina
http://data.giss.nasa.gov/
GISS Land+Ocean Global Temperature
Climate Response to Radiative ForcingClimate Response to Radiative Forcing
ΔT = F
Solar Irradiance Cycle ΔT = 0.1oC F = 0.15 Wm-2 (0.850.7/4)
= 0.67oC per Wm-2
BUT…. response to cyclic decadal forcing is assumed to be attenuated by 5
compared with “equilibrium” response
surface temperature change
forcing
climate sensitivity IPCC range: 0.2-1oC per Wm-2
paleoclimate: 0.75oC per Wm-2
Hansen, 2004
FE
ED
BA
CK
S
water vaporwater vapor
sea-ice/ sea-ice/ snow coversnow cover
cloud covercloud coverhttp://visibleearth.nasa.govhttp://www.hpl.umces.edu/~lzhong/mixed_layer/sml.htm
mix
ed l
ayer
El Chichon Pinatubo
SURFACE MIDDLETROPOSPHERE
El Nino
La Nina
LOWERSTRATOSPHERE
Tem
per
atur
e A
nom
aly
(K)
Solar Cycle Signals in Earth’s AtmosphereSolar Cycle Signals in Earth’s Atmosphere
solar increase warmingCO2 increase warmingvolcanoes cooling
solar increase warmingCO2 & CFC increase cooling
volcanoes warming
0 km8 km 20 km
O3 destruction
StratosphereStratosphere
unit optical depth
UV radiation(λ < 315 nm)
20 Wm-2
O2 photodissociation
O3 production
Sun, Sun, Stratosphere,Stratosphere,
OzoneOzone
near UV,VIS,IR Radiation(λ > 315 nm)1346 Wm-2
Sun
Pittock (1978): Sun-ozone correlations …“experiments in autosuggestion”
The Ozone Layer:The Ozone Layer:
EP/TOMS Total Ozone Sep 16, 2001
GSFC TOMS Total Ozone Sep 16, 2001
2.2%
Total Ozone 50S-50N ~ 280 DU
Recent VariationsRecent Variations
Nimbus 7
solar upper photosphere/ chromosphere2000-02-252000-02-25
1996-06-161996-06-16 UV radiation:200-295 nm+1.2%
4%
Stratosphere – Climate CouplingStratosphere – Climate Coupling
Radiative Coupling via Absorption and Emission
Rad
iativ
e Fo
rcin
g Se
nsiti
vity
NORTH ATLANTIC OSCILLATIONNORTH ATLANTIC OSCILLATION
Positive NAOPositive NAO Negative NAONegative NAO
•solar irradiance cycle modulatesstratospheric polar vortex• tropospheric circulation•NAO (solar min) AO (solar max)
Kodera, 2003
Lacis et al., 1979
Dynamical Coupling via Wind-Wave InteractionsChange Ozone & Temperature
Change Winds & Planetary Waves
Change Temperature Advection &Temperature
Change Winds & Planetary Waves
Change ClimateLo
wer
A
tmos
pher
eM
iddl
eA
tmos
pher
eShindell et al., 2003; Rind et al., 2004
StratosphereStratosphere
TroposphereTroposphere
ThermosphereThermosphereIonosphereIonosphere
solar EUV radiation λ< 100 nm
Alt
itu
de
solar increase warming CO2 increase warming
solar increase warmingCO2 increase cooling
solar increase warmingCO2 increase cooling
SPACE WEATHER
climate change
ozone depletionGLOBAL CHANGE
TOMS UV radiation exposure: January
solar min maxSun = +0.1KGHG = +0.2K
solar min maxSun = +0.3KGHG = -0.4K
solar min maxSun = 400KGHG = -3K
T
spacecraft drag
communication,navigation
solar EUV photon energy
solar wind kinetic energy (~protons)
corona
chromosphere heliosphere
16 JAN 03
Sun and Thermosphere-IonosphereSun and Thermosphere-Ionosphere
quiet Sun
response to EUV photons
response to particles, plasma, fields
500 km
temperature
neutral density
electron density
100%
Yohkoh: launched 30 AUG 1991Re-entered 12 SEPT 2005
solar EUV irradiance changes modulate upper atmospheric densities, affecting the orbits of >10,000 resident space objects
1999
Density at YOHKOH
Spacecraft DragSpacecraft Drag
International Space Station: 400 km YOHKOH Altitude
EUV Irradiance
July 1979
Space CommandRadar Fence
20031028 20:49
““Halloween” Solar StormHalloween” Solar Storm October 28th, 2003
NOAA National Weather Service http://www.sec.noaa.gov/
… at L1
SOHO/LASCO 20031028 12:42
heliosphere
X-ray photons
chromosphere-TR
EIT 30420031028 13:19
30 Rsun
8 minutes later ... X-class flare recorded by GOES
coronal mass ejection leaves the Sun ….
8 hours later... particles saturate SOHO/LASCO detector
surface
active region with big sunspot erupts ….
and reach Earth
energetic protons
SOHO/EIT 171 20031028 13:00
www.nas.edu.ssb/cover.html
Solar Variability Drives Solar Variability Drives Space WeatherSpace Weather
March 1989:Auroral Oval
solar photons & solar and magnetospheric particles
heat and ionize Earth’s atmosphere and ionosphere
Power System Events spacecraft drag, collisions, loss
aurora
currents induced in power grids
communications & navigation
spacecraft detector upsets
hazards to humans in space
Variability in the Space Era – Variability in the Space Era – past 30 yearspast 30 years Total Irradiance – Climate … where we live UV Irradiance – Ozone … our protective atmosphere EUV Irradiance, particles, plasma – Space Weather … technology
Sun-Earth System – Sun-Earth System – an overviewan overview The Sun, a Star, is our energy source The Earth, a planet, is our home
Relationships in the PastRelationships 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.
1613 Galileo 1995 SOHO
Earth’s surface temperature has increased in the last century..
1900-1950
1960-2000
http://giss/nasa/gov
Sun and Climate in Recent CenturiesSun and Climate in Recent Centuries
changes are non-uniform, globally and temporally
sunspot cycle amplitudes have increased from the Maunder Minimum to the Modern Maximum
Industrial-Era Climate Forcing: IPCC 2001Industrial-Era Climate Forcing: IPCC 2001
3
2
1
0
-1
-2
-3
1750
-200
017
50-2
000
CH4
N2Ohalocarbons
stratosphericozone
troposphericozone
2.4R
adia
tive
Forc
ing
(Wm
-2)
sulphate
fossil fuel
burning
biomass burning
mineral dust
landuse(albedo)
0.35 0.25 0.3
0.2 0.4 0.1 0.25 0.23
solar
indirect aerosol
CO2
aviationcontrails & cirrus
0.05
war
min
gco
olin
g
solar forcing
volcanic forcing
anthropogenic & solar forcing
Pre-Industrial Solar Forcing
F = 0.3 Wm-2 ΔT = 0.2oC = 0.6oC per Wm-2
Tamboora Coseguina Krakatoa
(Bradley & Jones, 1993)
Lean et al., 1995
(FSUN=ΔS0.7/4)
Climate Change in Recent CenturiesClimate Change in Recent Centuries
GCM simulation: ~ 4oC for 2×CO2Robinson et al., 2001
EBM simulation: ~ 2oC for 2×CO2Crowley, 2000
forcings
omitting solar forcing .. poorer tracking of centennial
variations .. higher sensitivity to GHGs
high solar activity low 14C low 18O high rainfall
Holocene Sun-Climate ConnectionsHolocene Sun-Climate Connections
18O in stalagmites in Oman track 14C for 3,000 years in mid-Holocene Neff et al., Nature, 2001
INTERTROPICAL INTERTROPICAL CONVERGENCE CONVERGENCE ZONEZONE
NORTH ATLANTIC NORTH ATLANTIC CLIMATECLIMATE
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 less drift ice southward
cosmogenic isotope changes - 14C in tree-rings, 10Be in icecores - imply long-term solar activity
Centennial-Millennial Solar VariabilityCentennial-Millennial Solar Variability
0.1%
… do they also imply long-term solar irradiance variations?
Mechanisms of Cosmogenic Isotope and Mechanisms of Cosmogenic Isotope and Solar Irradiance VariabilitySolar Irradiance Variability
Galactic Cosmic Ray Flux at Earth
Radial Interplanetary
Magnetic Field
open flux modulates cosmogenic isotopes
closed flux modulates irradiance
24 June 2002
EIT304
EIT284
surface magnetic fields of opposite polarity
open flux in coronal holes – extends to helio-sphere
closed flux in active regionsand network
phot
osph
ere
chro
mos
pher
eco
rona
Irradiance at Earth1365 Wm-2
0.0000007 Wm-2
MDI
Evolution of the Sun’s Surface Magnetic Field Evolution of the Sun’s Surface Magnetic Field Drives Long-Term Solar Irradiance ChangesDrives Long-Term Solar Irradiance Changes
sub-surface dynamo
surface magnetic fields of opposite polarity
www.hao.ucar.edu, Y.-M. Wang, N. Sheeley science.nasa.gov/ssl/pad/solar
diffusionpoleward meridional
flow
magnetic flux is transported by…. differential
rotation
0.08%
0.2%
Long-Term Solar Irradiance Simulated by a Flux Transport Model
magnetogram
Causes of Causes of Climate Climate ChangeChangein the in the
Recent PastRecent Past
Radiative Forcing 1750-2000
IPCC 2001: (Wm-2)Greenhouse Gases +2.4Ozone +0.15Solar +0.3Landuse -0.23Tropospheric -0.4 to -1.4 Aerosols
Hansen et al., 2001Tropospheric -0.6 Aerosols Empirical Reconstruction
+0.12
0.1K
0.9K
0.7K
Sun-Earth System:Sun-Earth System:Emerging QuestionsEmerging 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 gasesVertical 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 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”
Communication, NavigationCommunication, Navigation
Meier et al., GRL, 2001
ionospheric electron density response
X-ray and EUV irradiance variation
NRL SAMI2 model(Huber and Joyce)
Bastille Day 2000 Bastille Day 2000 solar eruptionsolar eruption flares
nemax=1.24×104fo2
Yohkoh SXT
• disrupts communications • degrades radar accuracy • disrupts/degrades navigation • degrades precision targeting
Meier et al., 2000
active region evolution solar cycle
reflection, refractiontime delays, phase shiftsfades, polarization rotation
Sun – Climate - Ozone: Sun – Climate - Ozone: Future Decadal VariabilityFuture Decadal Variability
Sun’s role in future climate change depends on irradiance cycles and trends relative to anthropogenic scenarios
solar cycle
C. Jackman, GSFC
Total OzoneTotal Ozone
Radiative ForcingRadiative Forcing
IPCC, 1995
Hansen et al, 2000
NPOESS ??GLORY
SORCETotal Solar IrradianceMonitoring
Coronal Mass EjectionSOHO/LASCO 1997-11-06 solar magnetic
cloud perturbs Earth’s magnetic field lines
Particle Transport
Particle-Plasma Wave Interactions
103 c
m-1 s
ec-1 s
tr-1
Coronal Mass EjectionsCoronal Mass Ejections
affects energetic particle penetration of Earth’s atmosphere
Propagate to Earth through the Propagate to Earth through the Heliosphere Heliosphere … hours to days
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