Multi-Model Comparisons of the Sensitivity of the Atmospheric Response to the SORCE Solar Irradiance Data Set within the SPARC-

SOLARIS Activity

K. Matthes (1,2), J.D. Haigh (3), F. Hansen (1,2), J.W. Harder (4), S. Ineson (5), K. Kodera (6,7), U. Langematz (2), D.R. Marsh (8), A.W. Merkel (4), P.A. Newman (9), S. Oberländer (2), A.A. Scaife (5), R.S. Stolarski (9,10), W.H. Swartz (11)

(1) Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany; (2) Freie Universität Berlin, Institute für Meteorologie, Berlin, Germany; (3) Imperial College, London, UK; (4) LASP, CU, Boulder, USA; (5)

Met Office Hadley Centre, Exeter, UK; (6) Meteorological Research Institute, Tsukuba, Japan; (7) STEL University of Nagoya, Nagoya, Japan; (8) NCAR, Boulder USA; (9) NASA GSFC, Greenbelt, USA; (10) John Hopkins University, Baltimore, USA; (11) JHU Applied Physics Laboratory, Laurel, USA

LASP seminar, 18 October 2011, Boulder

Outline

• Introduction/Motivation: Solar influences on climate

• SOLARIS project and objectives

• Uncertainty in solar irradiance data

• Preliminary results from the multi-model comparison

• Summary

• Outlook

2

IPCC (2007)

Introduction/Motivation: natural vs. anthropogenic climate factors

Solar Influences on ClimateReviews in Geophysics 2010

(open access sponsored by SCOSTEP)

1. Introduction2. Solar Variability

• Causes of TSI variability• Decadal-scale solar variability• Century-scale variability• TSI and Galactic cosmic rays

3. Climate Observations• Decadal variations in the stratosphere • Decadal variations in the troposphere • Decadal variations at the Earth’s surface • Century-scale variations

4. Mechanisms • TSI• UV • Centennial-scale irradiance variations• Charged particle effects

5. Solar Variability and Global Climate Change

6. Summary / Future Directions

Sunspot number

F10.7 cm flux

Magnesium ii

Open solar flux

Galactic cosmic ray counts

Total solar irradiance

Geomagnetic Ap index

Solar Variability(1975-2010)

Gray et al. (2010)

Labitzke, Labitzke and van Loon ....

30hPa Heights North Pole vs. F10.7 cm flux - February

Climate ObservationsCorrelations F10.7cm flux vs. 30hPa temperatures in July

....beginning with the pioneering work of Karin Labitzke and Harry van Loon

Tropospheric winds

Haigh, Blackburn, Simpson

Schematic of JetstreamNCEP Zonal Mean Wind (m/s)

(1979-2002)

11-year Solar Signal (Max-Min)

blocking events => cold winds from the east over Europe

blocking events longer lived for solar minima (Barriepedro et al., 2008)

Observed Annual Mean Solar Signal in Ozone (%/100 f10.7) and Temperature (K/100 f10.7)

Randel and Wu (2007)

+2%

+2%

+2%

95% significant

SAGE I/II Data (1979-2005)SSU/MSU4 (1979-2005)

Randel et al. (2009)

+1K

Solar Maximum:More UV radiation => higher temperaturesMore ozone => higher temperatures

11-year Solar Signal (Max-Min) Composites Dec/Jan/Feb

Climate Observations

Sea surface temperature:11 Max peak years

Precipitation:3 Max peak years

van Loon, Meehl, White

anthropogenic + natural forcings

natural forcings only

Surface Temperatures: IPCC

Solar variations cannot explain

observed 20th century global temperature

changes

long-term trend in solar activity appears be decreasing, as we come out of the current ‘Grand Maximum’

Climate Observations: Summary

Lots of examples of 11-yr solar influence in the stratosphere, troposphere and at the surface (e.g., temperatures (LvL), SSTs, mean sea level pressure, zonal and vertical winds, tropical circulations: Hadley, Walker, annular modes, clouds, precipitation), but predominantly regional response and sporadic in time.

No evidence that solar variations are a major factor in driving recent climate change; if anything, radiative forcing looks as though it is reducing as we possibly come out of the current grand maximum.

BUT, as we start to predict climate on a regional basis, it will be important to include solar variations in our models.

Climate Models:

Majority of coupled ocean-atmosphere climate models include only total solar irradiance (TSI) variations, i.e. the so-called ‘bottom-up’ mechanism.

More recent climate models now include the ‘top-down’ mechanism via the stratosphere.

Some specialist models also now include charged particle effects, e.g. energetic particle fluxes, solar proton events etc.

Mechanisms: Sun - Climate

Gray et al. (2010)

Gray et al. (2010)

based on Kodera andKuroda (2002)

“Top-down mechanism”

u

Stratospheric waves(direct solar effect) Tropospheric waves

(response to stratospheric changes)

Matthes et al. (2006)

„Top-down“: Dynamical Interactions and Transfer to the Troposphere

10-day mean wave-mean flow interactions (Max-Min)

EPF

Modeled Signal near Earth SurfaceMonthly mean Differences geop. Height (Max-Min) – 1000hPa

+

- -

+

+

+

Significant tropospheric effects (AO-like pattern) result from changes in wave forcing in the stratosphere and troposphere which changes the meridional circulation and surface pressure

Matthes et al. (2006)+2K

ΔT

SPARC-SOLARIS

SOLARIS

Goal: investigate solar influence on climate with special focus on the importance of middle atmosphere chemical and dynamical processes and their coupling to the Earth‘s surface with CCMs, mechanistic models and observations

Activities:• detailed coordinated studies on „top-down“ solar UV and „bottom-up“ TSI mechanisms as well as impact of high energy particles• solar irradiance data recommendations(CCMVal, CMIP5)

SOLARIS Activities

• regular workshops: 2006 (Boulder, CO/USA), 2010 (Potsdam, Germany), 8-12 Oct 2012 (Boulder, CO/USA)

• side meetings: 2005 (IAGA conference, Toulouse, France), 2008 (SPARC,Bologna, Italy), 2010 (SCOSTEP, Berlin, Germany), 2011 (IUGG, Melbourne, Australia)

• new website: http://sparcsolaris.gfz-potsdam.de

2006 2010

SOLARIS Objectives

• What is the characteristic of the observed solar climate signal?

• What is the mechanism for solar influence on climate? (dynamical and chemical response in the middle atmosphere and its transfer down to the Earth’s surface)

• How do the different natural and anthropogenic forcings interact? (solar, ENSO, QBO, volcanoes, CO2)

19

SOLARIS Experiments and Analyses

• Coordinated model runs to investigate aliasing of different factors in the tropical lower stratosphere

• Coordinated model runs to study the uncertainty in solar forcing

• Analysis of CMIP5 simulations

20

Uncertainty in Solar Irradiance Data

21

Lean et al. (2005) Krivova et al. (2006)

Solar Max-MinLean vs. Krivova

Haigh et al., Nature (2010)

2004-2007Lean vs. SIM/SORCE

• larger variation in Krivova data in 200-300 and 300-400nm range• SORCE measurements from 2004 through 2007 show very different spectral distribution (in-phase with solar cycle in UV, out-of-phase in VIS and NIR)

=> Implications for solar heating and ozone chemistry

1. Compare Existing Model Runs

Participating Models

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Caveat: all the models used a slightly different experimental setup, so it won’t be possible to do an exact comparison

Experimental Design

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Time series of F10.7cm solar flux

„solar max“ 2004

„solar min“ 2007

January Mean Differences(25N-25S)

24

Shortwave Heating Rate (K/d) Temperature (K)

Pre

ssure

(hPa)

Heig

ht (km

)

Heig

ht (km

)Pre

ssure

(hPa)

NRL SSISORCE

• larger shortwave heating rate and temperature differences for SORCE than NRL SSI data• FUB-EMAC and HADGEM only include radiation, not ozone effects

January Mean Differences(25N-25S)

25

Ozone (%) Temperature (K)

Pre

ssure

(hPa)

Pre

ssure

(hPa)

Heig

ht (km

)

Heig

ht (km

)

Pre

ssure

(hPa)

• larger ozone variations below 10hPa and smaller variations above for SORCE than NRL SSI data• height for negative ozone signal in upper strat. differs between models

NRL SSISORCE

Shortwave Heating Rate Differences January (K/d)

EMAC-FUB GEOS IC2DHadGEM WACCM

NR

L SS

ISO

RC

E

• NRL SSI shortwave heating rates: 0.2 to 0.3 K/d • SORCE shortwave heating rates: 0.7 to >1.0 K/d (3x NRL SSI response)

27

Temperature Differences January (K)

EMAC-FUB GEOS IC2DHadGEM WACCM

NR

L SS

ISO

RC

E

Ozone Differences January (%)

EMAC-FUB GEOS IC2DHadGEM WACCM

NR

L SS

ISO

RC

E

• larger ozone variations below 10hPa and smaller variations above for SORCE than NRL SSI data• height for negative ozone signal in upper strat. differs between models

Zonal Wind Differences January (m/s)

EMAC-FUB GEOS IC2DHadGEM WACCM

NR

L SS

ISO

RC

E

• consistently stronger zonal wind signals for SORCE than NRL SSI data• wind signal in SORCE data characterized by strong westerly winds at polar latitudes, and significant and similar signals in NH troposphere

SORCE Wind Differences NH Winter

30

EMAC-FUB GEOS IC2DHadGEM WACCM

Dec

Jan

Feb

SORCE Geopot. Height Differences January (gpm)

EMAC-FUB GEOS HadGEM WACCM

500

hPa

100

hPa

10 h

Pa

• NAO/AO positive signal during solar max strongest for HadGEM

Solar Cycle and the NAO

32

Solar Max: NAO positive (high index)

Solar Min Surface Pressure Signal

33

Ineson et al. (2011)

Model (HadGEM) Observations (Reanalyses)

Solar Cycle and the NAO

34

Solar Max: NAO positive (high index)

Solar Min: NAO negative (low index)

Matthes (2011)

Summary

Models show consistently larger amplitudes in 2004 to 2007 solar signals for SORCE than for NRLSSI spectral irradiance data in temperature, ozone and shortwave heating rates

For tropical ozone, the SORCE signal differs completely from the NRL SSI signal in showing a positive signal throughout the stratosphere whereas the latter shows a reversal from negative to positive values in the middle stratosphere

Impact on NAO, opportunity for improving decadal climate predictions

Results for the SORCE spectral irradiance data are provisional because of the need for continued degradation correction validation and because of the short length of the SORCE time series which does not cover a full solar cycle

35

Outlook

In order to study the differences in atmospheric response between the models in a more consistent way and investigate the surface climate response, coordinated studies with a typical solar max (2002) and solar min (2008) spectrum from the NRL SSI and the SORCE data will be provided to perform a number of sensitivity experiments.

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Thank you very much!

Estes Park/RMNP, 10-15-2011

Extra slides

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