CM-SAF surface radiation

1. Deutscher Wetterdienst 23rd GIST meeting in Offenbach 29.04.2005 CM-SAF surface radiation R. Hollmann, R.W. Mueller, H.D. Behr, P. Albert, A. Gratzki, Meteo Swiss

2. Introduction CM-SAF Surface radiation budget Algorithms used results with MSG cloud mask validation Conclusion Outline of talk

3. Mandate of CM-SAF: support climate monitoring at regional scale the generation of a thematic climate data record in an operational off - line environment the generation of long-term validated, homogeneous and consistent data sets Beside the mandate of CM-SAF the Solar-Energy Community benefits from the CM-SAF radiation products Motivation

4. Products: SOL: surface outgoing longwave SDL: surface downwelling longwave SIS: surface incoming shortwave SAL: surface albedo SRB: surface radiation budget (SNL/SNS) 15x15 km sinusoidal projection. Monthly and daily mean (AVHRR, MSG), mean diurnal cycle (only MSG) Covered area: 30° N to 80° N, 60° W to 60° E Operational processing and delivery of NOAA-AVHRR based products has been started 01.01.2005 MSG based products are currently pre-operational (~available for public Aug/Sep 2005 (tbc)) Surface Radiation budget products

5. V3 V2 MSG (rad & clouds) HCP (ATOVS & MSG) Area Extension EPS Merging V1 NOAA (rad & clouds) CM-SAF Surface Radiation Budget: CM-SAF: Schedule & Versioning Full Operations Phase Initial Operations Phase I 2004 I 2005 I 2006 I 2007 I 2008 I 2009 23rd GIST

6. Beta-user?! • Passive House Institute, (J. Schnieders), Darmstadt, Germany • Fraunhofer Institute for Solar Energy Systems (Chr. Reise), Freiburg, Germany • DWD, Regional Office Hamburg, solar energy specific radiation maps • Scientific User‘s (tbc): • RADAGAST (within AMMA framework), A. Slingo, Reading, UK • DLR (M. Schrödter-Homscheidt), Oberpfaffenhofen, Germany • Spain Met. Service (J. L. Camacho, Guerrero) • Looking for more beta-user!!! -> • -> have a look at http:\\www.cmsaf.dwd.de

7. RTM library libRadtran for MLB-LUTs Bernhard Mayer (DLR) and Arve Kylling (NILU) SHDOM for cloud LUTs Frank Evans AVHHR TOA-flux with ERBE ADM (DWD), cloud products, nowcasting SAF (SMHI). TOA-flux for GERB/SEVIRI is calculated by RMIB. Overview SIS Algorithm

8. Overview SIS Algorithm cloudmask SAT AVHRR GERB/SEVIRI TOA flux ADM Cloud-free ? CLOUD-LUT Relation G-TOA for clear-sky atmospheric states (9SZW) and 10 CODs CLEAR-SKY: MLB-LUT G for clear-sky atmospheric states Clear-sky Atmospheric state Ozon, H2O, Aerosole G G

9. Example MSG products Monthly mean 2004,07: top SDL, SOL; bottom SIS, SAL

10. Example products Monthly mean 2004,07: top SNL; bottom SNS

11. Example products Monthly mean diurnal cycle of SIS for April 2005 Rem.: at the moment no GERB-data are available -> the SIS-Algorithm is run with the SEVIRI only based TOA albedo

12. SOL: Based on Plancks radiation law for black bodies. Surface temperature from GME analysis SDL: Adaption of Gupta algorithm T and H2O from GME analysis Cloudmask and –height retrieved from AVHRR or MSG with nowcasting-SAF algorithms (SMHI, MeteoFrance) Overview Longwave

13. 4-5 stations: Payerne, Carpentras, Lindenberg, Cabauw (Ny-Alesund). Ongoing validation of the operational products Validation of reference months. Base for Initial operations phase. To analyse comparable results with the goal to improve the algorithm. To track the effect of changes in the algorithm. Overview Validation

14. Overview Validation Mean absolute bias of monthly means over all stations and months (4 stations, 2 month) . BIAS in W/m² BIAS in % SOL 7.6 2 SDL 9.5 2.75 SIS 2.9 2.5

15. Overview Validation First validation of MMDC: July 2004, Carpentras-Station Green: surface obs black: MSG derived

16. 10 W/m² „target accuracy“ für monthly means (SIS,SOL,SDL) are in general achieved. Problems in the Alpine region, especially for the longwave radiation. Support for heterogeneous terrain by MeteoSwiss. Planned: Routine (Automatized) quality check with reference data set. Validation for more stations and month. Acknow.: For providing data for validation to MeteoSwiss, MeteoFrance, KNMI, DWD, AWI Conclusion Validation

17. Comparison of MSG cloud fraction with Synop observations April, May, October 2004 Validation of MSG cloud fraction

18. Validation of MSG cloud fraction SYNOP MSG rel. difference difference

19. Better agreement over land than over sea Day / night dependence? Best agreement where number of SYNOP observations is highest Validation of MSG cloud fraction

20. CM-SAF Surface Radiation Budget: Conclusion & outlook Outlook: • Operational production based on NOAA-AVHRR since Jan 2005 • Operational production based on MSG will start Aug/Sep 2005 (tbc) • Surface Radiation Processing; • mean differences for SIS ~ 10 W/m² • mean differences for SDL ~ 10 W/m² • Ongoing validation; • selected reference target stations with quick data availability • TOA albedo comparison MSG/GERB vs. AVHRR • improvement of LUT-approach • new background maps for aerosol properties • merging of both data set • User Workshop 29-31. August 2005 in Nuremberg (Germany).

22. Clear-sky MLB-LUT MLB: modified Lambert Beer relationship (Mueller et al. 2004) LAT,LON MLB-LUT: G for 2 SZA different AOD, ssa, gg USS-stand. profile, surf. albedo 0.2 GADS/OPAC or MPI Hamburg Aerosol climatology AOD ssa, gg G interpolated Aerosol-space GME H2O O3 profile H2O, O3 correction absorb constituents H2O,O3 Surface albedo FMI or background Albedo correction of effect surface albedo G

23. Cloudy-sky ‘traditional’ LUT SAT ADM LAT,LON TOA flux GME H2O O3 profile LUT: TOA flux – G ratio for 9 SZA, 10 COD, 5 H2O, 7 Albedo, 3 O3, 5 atm. profile H2O, O3 surfacealbedo FMI or background-alb Albedo G interpolated, no aerosols GADS/OPAC or MPI Hamburg Aerosol Climatology Correction for Aerosols AOD ssa, gg G