Solar Spectral Irradiance (SSI) changes, atmospheric effects? J. Fontenla NorthWest Research...
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Transcript of Solar Spectral Irradiance (SSI) changes, atmospheric effects? J. Fontenla NorthWest Research...
Solar Spectral Irradiance (SSI) changes, atmospheric effects?
J. Fontenla
NorthWest Research Associatesand
LASP-University of Colorado
The topic: SSI changes, and does it matter?
• Solar Physics issues:– Solar atmosphere structure and SSI– Non-LTE radiative transfer– Solar magnetic (sunspot) cycle– Magnetic effects on the solar atmospheric layers
• Atmospheric issues:– Photochemistry– Heating of various layers of the Earth atmosphere– Ocean currents and energy transport– Effects of all the above on circulation
The solar research on SSI modeling • Emitted intensity spectrum =>solar atmospheres• 1970s: HSRA, BCA, Gingerich, Peytremann, Holweger & Muller• Avrett et al. 1981 VAL non-LTE, Athay & Thomas non-LTE and
chromosphere, Mihalas, Kurucz LTE stellar models, 1980s• Transition region and Lyα, Fontenla et al. 1993 FAL, 1990s
• Solar atmospheres => SSI calculations• Solanki/Unruh 1998, 3 component, LTE• RISE models 1999, 6 components, full/approx NLTE• Shapiro/Krivova 2011, full NLTE in few species/levels• SRPM models 2011, 9 components, resolved over the disk, full
NLTE in 50 species/over 13,000 levels/over 170,000 atomic/ionic lines and over 550,000 molecular lines (LTE).
SSI spectral features and atmospheric regions
Photosphere: visible,IR continuum and weak absorption lines
Lower chromosphere: NUV, visible, IR absorption lines
Upper chromosphere: deep absorption line cores and UV emission lines
Transition region: EUV/FUV emission lines
Fontenla, Avrett, & Loeser 1991, FAL 2, The Astrophysical Journal, 377:712-725
Solar Surface Features
A-weak internetwork (new)B-internetwork (changed C)D-network (new)E-active network (changed F)H-normal plage (new)
P-bright plage (changed P)Q-very hot plage (new)S-sunspot umbra (temp)R-sunspot penumbra (new/temp)
Models of solar atmospheric features
105 1044000
5000
6000
7000
8000
9000
Feature C model 1001 Feature H model 1004 Feature P model 1005
Te
mp
era
ture
(K
)
Pressure (dyne cm-2)
Fontenla et al. 2011, JGR, 116, full NLTE, Tmin very different
Fontenla et al. 2006,The Astrophysical Journal, 639:441–458,Models cross at ~6500 K, in NLTE.
Solanki & Unruh 1998, Astron. Astrophys. 329, 747-753, LTE.No crossing in these models, SSI computed in LTE from FAL P with modifications.
Fontenla et al. 2011, JGR, 116, D20108
0 40 80 120 160 200 240
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2 CA CB CD CF CH CP CQ
Te
mp
era
ture
(M
K)
Height (Mm)
Contributions to Quiet-Sun TSI (1360 W m-2):•Photosphere: ~1351 W m-2
•Chromosphere: ~8 W m-2 (power >> TSI observed changes)•Corona+Transition-region: ~70 mW m-2
Transition-region and Coronal layersPhotospheric and chromospheric layers
Computed vs observed SSI
Some observations considered for SRPM set of atmospheric models
Topka et al. 1997, The Astrophysical Journal, 484:479-486
Sanchez Cuberes et al. 2002, The Astrophysical Journal, 570:886–899
Features continuum contrast varies with wavelength and heliocentric angle, corresponds to the slope of T vs p, SRPM model set used detailed radiance observations
San Fernando ObservatoryGround-based radiance observations confirm that ARs are dim in the visible,
over the solar cycle plage near the limb do not increase the visible SSI.
Preminger et al. 2011, ApJ
Ca II K
Red
Blue
Controversy1: Calculated SSI behaviorSolanki & Unruh 1998,Astron. Astrophys. 329, 747-753
According to this paper: «The dotted curve shows the observed relative irradiance variation for λ < 400 nm between solar activity minimum and maximum vs. wavelength, compiled by Lean et al. (1997) and extrapolated to longer wavelengths by Lean (1991). »
100 1000 100001E-5
1E-4
1E-3
0.01
0.1
corr nocorr - corr - nocorr nrlssi - nrlssi
SS
I/SS
I
Wavelength (nm)
Relative changes between Solar Cycle 23 peak/min that I am using for WACCM4 simulation runs.Nocorr – Fontenla et al 2011, SRPM + PSPT imagesCorr - same as above with a correction to match TSINRLSSI – WACCM4 default.“Lean_1610-2140_ann_c100405”
“nocorr” SSI (wavelength,time)
Lower- and upper-chromospherebright/dark fine structure, 1-D models only a first
approximation to the net medium-resolution
Upper-chromosphere
Lower chromosphereExtension of the granulation structure. Some localized energy dissipation in the walls of downdrafts. Loops and mechanical dissipation
3D Radiation Transport & NLTE
1 103
1 104
1 105
1 106
4000
6000
8000
SRP M 306Stein & NordlundSRP M 306 * 0.95
Height (km)
Temp
eratu
re (K
)
mostlyconvectivetransport
mostly radiativetransport
Pressure (dyne cm^-2)
1 103
1 104
1 105
1 106
0
200
400
SRPM 306Stein & NordlundSRPM 306 + 30 km
Pressure (dyne cm^-2)
Heig
ht (k
m)
Mg I 4572C I 5381 CN band
Computed for photospheric convection simulation snapshotwith data from Stein & Nordlund 2005
800 nm 1200 nm 1600 nm500 nm
Network and its change over the cycle, what is “quiet-Sun”?
1 1.21 10
4
1 103
0.01
0.1
1
Intensity
Rel
ativ
e ar
ea
A B D F H P
low
peak
In the so-called “quiet-Sun”, i.e. locations where no obvious AR are present, the intensity distribution of the network is observed to change with the solar cycle (maybe not strictly in phase with the sunspot index).
Intensity distribution at the disk center
A 1101 1374.60
B 1001 1382.19
D 1002 1388.15
F 1003 1391.44
H 1004 1400.86
P 1005 1419.14
S 1006 265.97
R 1007 1103.82
Q 1008 1428.82
Feature, model, TSIThis has implications for SSI and for TSI.But available images lack reliable absolute calibration. Day to day matching was done with the median.
Time series of solar spectral variability from SORCE/SIM
Controversy2: NUV Observations
Various instruments claiming reliable calibration for long term
Most instruments show variation of about ~50/1000~5% except for SUSIM.Only SUSIM measured one peak, since UARS/SOLSTICE hardware failed in 2000Both SORCE instruments show ~6% variations; their decreasing SSI turned around to increasing as SC 24 started in ~2010, but later data is not shown here.
NUV effects on O3
180 200 220 240 260 280 300 320 340 360 380 4000
2
4
6
8
nocorrcorrnrl
Wavelength (nm)
delta
.Flu
x/F
lux_
min
(%
/100
F10
.7 u
nits
)
Calculations were carried out by Merkel et al (see GRL38, L13802 2011), using SORCE data extrapolated in time. These are done with WACCM3 in static SSI runs.Other authors also made simplified calculations showing important differences.
I am carrying out transient WACCM4 (NCAR Community Earth System Model 1.0.3 ) runs with coupled atmosphere, ocean, land, and ice. O3 is included but so are many other processes.
CESM (WACCM4) for SSI study
• Transient runs 1955-2005 including all observed forcing. Imposing observed QBO.
• SSI: wavelength < 120 nm uses F10.7 proxy
• SSI: 120 nm < wavelength < 100 μm:– “const” uses time independent low activity SSI– “nocorr” from SRPM + PSPT & Meudon images,
repeats SC23 (with stretching) – “corr” same as above but with a correction to
match observed TSI, still under development– “nrlssi” using the default SSI in CESM, from Lean
SSI “nocorr” model of SC23, vs NRLSSI
2000 20051358
1360
1362
SRPMLean
TSI
Year
Irra
dian
ce
X0 1600 6.185 10
3
2000 20051.58
1.581
1.582
1.583
1.584
SRPMLean*0.995
6185.5 nm
Year
Irra
dia
nce
X0 1200 3.592 10
3
2000 200513.01
13.015
13.02
13.025
13.03
SRPMLean*0.995
3592.5 nm
Year
Irra
dia
nce
2000 20051970
1975
1980
1985
1990
SRPMLean*0.978
448.5 nm
Year
Irra
dia
nce
2000 20051040
1045
1050
1055
1060
SRPMLean*0.972
368.5 nm
Year
Irra
dia
nce
2000 20054
5
6
7
8
9
10
SRPMLean
121.5 nm
Year
Irra
dia
nce
2000 20051592
1594
1596
1598
1600
1602
SRPMLean*1.006
648.5 nm
Year
Irra
dia
nce
X0 670 942.5
2000 2005794
795
796
797
SRPMLean*0.97
942.5 nm
Year
Irra
dia
nce
X0 800 1.593 10
3
2000 2005252
252.2
252.4
252.6
252.8
SRPMLean*1.018
1593.5 nm
Year
Irra
dia
nce
mW m-2 nm-1 W m-2
Follow some preliminary results• Only from one complete run of each case, the 3
years near the minimum, over 4 solar cycles were averaged and compared.
• The same was done for and 3 years near the maximum over 4 solar cycles.
• Then, the averages of 12 years near min and 12 years near max were subtracted to show the effect of SSI change.
• The maps shown below are for the DJF season, the JJA patterns are different.
• The zonal means are annual.
• More instances are running to form an ensemble. However, Earth behavior is only one instance.
Preliminary WACCM surface resultsdelta.CLOUDT const
delta.TS const
delta.PS const
delta.CLOUDT nocorr delta.CLOUDT nrlssi
delta.PS nocorr delta.PS nrlssi
delta.TS nocorr delta.TS nrlssi
longitudelatitude
Cloud fraction
Surfacte temperature
Surface pressure
ENSO and “natural” variability issues
1960 1970 1980 1990 20004
2
0
2
4
ENSO 3.4 region (DJF)
Year
delta
.T (
K)
Volcanic eruptions are a big issue:Mt. St. Helens 1980El Chichon 1982Pinatubo 1991
1960 1970 1980 1990 2000
5
0
5
10
constcorr*nocorrnrlssi
ENSO SOI
Year
delta
.PS
(hP
a)
Does the SSI choice affect these?More “realizations” are neededHow to cancel volcanic effects?
(DJF)
1960 1970 1980 1990 2000300
200
100
0
100
constcorr*nocorrnrlssi
Alleutian Pressure (DJF)
Year
delt
a.P
S (
hPa)
Zonal mean T and H2O changes
-80 -60 -40 -20 0 20 40 60 803
2
1
0
-1
-2
-3
Latitude
Lo
g1
0(p
ress
ure
)
-0.02000-0.01600-0.01200-0.008000-0.0040000.0000.0040000.0080000.012000.016000.02000
-80 -60 -40 -20 0 20 40 60 803
2
1
0
-1
-2
-3
Latitude
Lo
g1
0(p
ress
ure
)
-0.02000
-0.01600
-0.01200
-0.008000
-0.004000
0.000
0.004000
0.008000
0.01200
0.01600
0.02000
-80 -60 -40 -20 0 20 40 60 803
2
1
0
-1
-2
-3
Latitude
Lo
g1
0(p
ress
ure
)
-0.02000-0.01600-0.01200-0.008000-0.0040000.0000.0040000.0080000.012000.016000.02000
-80 -60 -40 -20 0 20 40 60 803
2
1
0
-1
-2
-3
Latitude
Lo
g1
0(p
ress
ure
)
-2.000-1.600-1.200-0.8000-0.40000.0000.40000.80001.2001.6002.000
-80 -60 -40 -20 0 20 40 60 803
2
1
0
-1
-2
-3
Latitude
Lo
g1
0(p
ress
ure
)
-2.000-1.600-1.200-0.8000-0.40000.0000.40000.80001.2001.6002.000
const nocorr
-80 -60 -40 -20 0 20 40 60 803
2
1
0
-1
-2
-3
Latitude
Lo
g1
0(p
ress
ure
)
-2.000-1.600-1.200-0.8000-0.40000.0000.40000.80001.2001.6002.000
nocorr-const
H2O(relat)
T (K)
“const” displays changes that are not due to the SSI choice, difference of difference can eliminate some but is affected by the “noise” in both “nocorr” and const”
Issues analyzing simulation results to separate SSI effects from other effects
tropical (±25 deg) annual differences between peak and min years
-4 -2 0 2200
300
T (
K)
Log10(pressure)
-4 -2 0 2
0
2
4
de
lta.T
(K
)
Log10(pressure)
T nocorr const nocorr-const
-4 -2 0 20
2
4
6
8
10
12
14
O3
(p
pm
)
Log10(pressure)
-4 -2 0 2-2
0
2
4
6
8
10
12
de
ltare
l.O3
(%
)
Log10(pressure)
O3 nocorr const nocorr-const
-4 -2 0 2
0.1
1
10
100
1000
10000
H2
O (
pp
m)
Log10(pressure)
-4 -2 0 2
-2
0
2
4
De
lta.H
2O
Log10(pressure)
H2O nocorr const nocorr-const
tropos
stratos
mesos
thermos
Other WACCM Simulation Interesting Results
The NRLSSI dif. of dif. have also some of this behavior on the Pacific Ocean Warm Pool but the details are quite different. Also, NRLSSI results show several differences in other regions, e.g. the patterns in Mexico Pacific area, Brasil Atlantic, and Madagascar Indian Ocean which are not shown by “nocorr” results
= DifDif.FSDSShows the downwelling solar shortwave flux at the surface increases of ~30 W m-2 at the Pacific Ocean Warm Pool region at solar max times. But was shown before that the surface temperature does not increase much there. Ocean effects, Kuroshio stream, moderate T?
Nocorr-Const
NRLSSI-Const
Ocean gyres
Ocean currents couple to atmospheric winds and tropospheric energy transport. This is represented in CESM1.0.3/WACCM4 by the integration of the atmospheric model (CAM2) with the deep ocean model (POP).
The tropospheric and ocean phenomena are very tangled!
Analysis is very complex but these simulations contain a wealth of data which could nail down the physical processes induced by SSI changes.That is, if one could also figure out other forcing and variability.
Future work• All the maps shown above is for DJF season, similar ones for JJA
season were done.
• Still improving “corr” SSI case by reprocessing images into “corr2”, hope to have it by end of year 2012 .
• Performing runs for more instances of all SRPM cases, necessary to separate natural variability and SSI effects 4 instances are the target.
• Analysis of the data for ocean and other components of CESM model remains to be done.
• Comparison between CESM 1.0.3 and MODTRAN@ atmospheric radiative heating/cooling to be carried out to evaluate spectral model and resolution effects.
• FUV/EUV SSI ongoing modeling for replacing F10.7 proxy and for forecast of thermospheric neutral density and ionization.
Dark active regionsA nice example on 2/3/2007 shows two large magnetic active regions sunspots side-by-side and one is associated with a lot of chromospheric and coronal heating but the other is not showing much heating.
The magnetic flux of the sunspots is not too different but the bright region is bipolar and more complex.