Multi-model intercomparison of the impact of SORCE measurements in climate models

1. Multi-model intercomparison of the impact of SORCE measurements in climate models TOSCA WG1 Workshop 14-16 May 2012, Berlin K. Matthes (1), J.D. Haigh(2), F. Hansen (1), J.W. Harder(3), S. Ineson(4), K. Kodera(5,6), U. Langematz (7), D.R. Marsh (8), A.W. Merkel (3), P.A. Newman (9), S. Oberländer (7), A.A. Scaife(4), R.S. Stolarski(9,10), W.H. Swartz(11) (1) Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), Kiel, Germany; (2)Imperial College, London, UK; (3)LASP, CU, Boulder, USA; (4) Met Office Hadley Centre, Exeter, UK; (5) Meteorological Research Institute, Tsukuba, Japan; (6)STEL University of Nagoya, Nagoya, Japan; (7) Freie Universität Berlin, Institute für Meteorologie, Berlin, Germany; (8) NCAR, Boulder USA; (9) NASA GSFC, Greenbelt, USA; (10)John Hopkins University, Baltimore, USA; (11) JHU Applied Physics Laboratory, Laurel, USA

2. Outline Motivation Model Descriptions and Experimental Design Preliminaryresultsfromthe multi-model comparison Summary Outlook

3. Motivation • SORCE/SIM measurements from 2004 to 2007: increased solar spectral irradiance at UV and IR wavelengths even as solar and TSI decreased => • SIM spectral data into climate models => „the effects of solar variability on temperature throughout the atmosphere may be contrary to current expectations“ (Haigh et al., 2010) • => higher solar activity cools Earth But: • SIM trends relative to TSI and solar activity during solar min => unlikely to be solar in origin • „It is doubtful that simulations of climate and atmospheric change using SIM measurements are indicative of real behavior in the Earth‘s climate and atmosphere.“ (Lean and DeLand, 2012) • „SIM‘s solar spectral irradiance measurements from April 2004 to December 2008 and inferences of their climatic implications are incompatible with the historical solar UV irradiance database […] but are consistent with known effects of instrument sensitivity drifts.“ (Lean and DeLand, 2012) • „To prevent future research following a path of unrealistic solar-terrestrial behavior, the SORCE SIM observations should be used with extreme caution in studies of climate and atmospheric change until additional validation and uncertainty estimates are available.“(Lean and DeLand, 2012)

4. Motivation • 2 questions • Do the SIM measurementsprovidetrue solar behaviororaretheserelatedtoinstrumentdrifts? • Whatistheeffectof larger UV variability on theEarth‘satmosphere? (focusofthisstudy)

5. “Top-down mechanism” based on Kodera and Kuroda (2002) Gray et al. (2010)

6. EPF Stratosphericwaves (direct solar effect) Troposphericwaves (response to stratospheric changes) „Top-down“: Dynamical Interactions and Transfer totheTroposphere10-day meanwave-meanflowinteractions (Max-Min) u Matthes et al. (2006)

7. Modeled Signal near Earth SurfaceMonthlymeanDifferencesgeop. Height (Max-Min) – 1000hPa + + - - + + ΔT +2K Matthes et al. (2006) Significanttroposphericeffects (AO-likepattern) resultfromchanges in waveforcing in thestratosphereandtropospherewhichchangesthe meridional circulationandsurfacepressure

8. Uncertainty in Solar Irradiance Data 2004-2007 Lean vs. SIM/SORCE Solar Max-Min Lean vs. Krivova Haigh et al., Nature (2010) Lean et al. (2005) Krivova et al. (2006) • 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

9. 1. Compare Existing Model RunsParticipating Models Caveat: all the models used a slightly different experimental setup, so it won’t be possible to do an exact comparison

10. Differences in Experimental Setup

11. Experimental Design Time series of F10.7cm solar flux 2004: “solar max” (declining phase of SC23) „solar max“ 2004 „solar min“ 2007 2007: “solar min” (close to minimum of SC23)

12. JanuaryMeanDifferences(25N-25S) ShortwaveHeating Rate (K/d) Temperature (K) Pressure (hPa) Pressure (hPa) Height (km) Height (km) • larger shortwave heating rate and temperature differences for SORCE than NRL SSI data • FUB-EMAC and HadGEM only include radiation, not ozone effects NRL SSI SORCE

13. JanuaryMeanDifferences(25N-25S) Ozone (%) Temperature (K) Pressure (hPa) Pressure (hPa) Height (km) Height (km) • 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 SSI SORCE

14. Shortwave Heating Rate Differences January (K/d) HadGEM IC2D WACCM EMAC-FUB GEOS NRL SSI SORCE • 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)

15. TemperatureDifferencesJanuary (K) HadGEM IC2D WACCM EMAC-FUB GEOS NRL SSI SORCE • NRL SSI temperatures: 0.5 to 1.0 K (stratopause) • SORCE temperatures: 2.5 to 4.0 K (4-5x NRL SSI response) • colder polar stratosphere

16. OzoneDifferencesJanuary (%) HadGEM IC2D WACCM EMAC-FUB GEOS NRL SSI SORCE • 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

17. Zonal Wind DifferencesJanuary (m/s) HadGEM IC2D WACCM EMAC-FUB GEOS NRL SSI SORCE • 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

18. SORCE Wind Differences NH Winter HadGEM IC2D WACCM EMAC-FUB GEOS Dec Jan Feb

19. SORCE Geopot. Height Differences January (gpdm) HadGEM WACCM EMAC-FUB GEOS 500 hPa NAO/AO positive signal during solar max strongest for HadGEM and WACCM 100 hPa 10 hPa

20. Solar Cycle and the NAO Solar Max: NAO positive (highindex) • Colderstratosphere => stronger NAO, • i.e. strongerIcelandlow, higher • pressureoverAzores • amplifiedstormtrack • mild conditionsover northern • Europe andeastern US • => dry conditions in themediterranean

21. Solar Min Surface Pressure Signal Model (HadGEM) Observations (Reanalyses) 25 (50%) of interannual standarddeviation 90 (95%) significances Ineson et al. (2011)

22. Solar Cycle and the NAO Solar Min: NAO negative (lowindex) Solar Max: NAO positive (highindex) Matthes (2011)

23. Summary • Consistently larger amplitudes in 2004 to 2007 in solar signals for SORCE than for NRL SSI data in temperature, ozone, shortwave heating rates, zonal winds and geopotential heights • Larger ozone variations below 10hPa and smaller variations above for SORCE than NRL SSI data; height for negative ozone signal in upper stratosphere differs between models • Solar cycle effect on AO/NAO contributes to substantial fraction of typical year-to-year variations and therefore is a potentially useful source of improved decadal climate predictability (Ineson et al. (2011))  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

24. Outlook Next step: coordinated sensitivity experiments for a typical solar max (2002) and solar min (2008) spectrum from the NRL SSI and the SORCE data to investigate the atmospheric and surface climate response between the models in a more consistent way => White paper until early December, experiments to be started early 2012 in order to be ready for the SOLARIS/HEPPA workshop 8-12 October 2012 here in Boulder!

25. Thankyouverymuch! Estes Park/RMNP, 10-15-2011