Federal Department of Home Affairs FDHA Federal Office

  • Slides: 15
Download presentation
Federal Department of Home Affairs FDHA Federal Office of Meteorology and Climatology Meteo. Swiss

Federal Department of Home Affairs FDHA Federal Office of Meteorology and Climatology Meteo. Swiss Verification of global radiation of COSMO-7 with MSG (Meteosat Second Generation) and ASRB network (Alpine Surface Radiation Budget) Matteo Buzzi [presented by Francis Schubiger] Meteo. Swiss COSMO General Meeting 2007 WG 5 Parallel Session 18 September 2007

MSG processing chain: Introduction work of CM-SAF (B. Dürr, Meteo. Swiss) • Usage of

MSG processing chain: Introduction work of CM-SAF (B. Dürr, Meteo. Swiss) • Usage of full spatial and temporal resolution of MSG satellites (pixel: ~ 1. 1 km x 1. 8 km, 15 min) • Processing for sun elevation angles > 5° only • Combination of 4 SEVIRI channels with High Resolution Visible (HRV) channel and their temporal evolution improves the distinction of clouds over snow covered areas • Estimation of surface incoming solar (SIS) radiation with HELIOSAT-1 Cloud-Index method • No input data necessary from NWP/GCM models Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] Photo: ESA 2

Verification data Meteosat Second Generation • Daily averages • shadowing effects considered • Resolution:

Verification data Meteosat Second Generation • Daily averages • shadowing effects considered • Resolution: 1. 1 x 1. 8 km • Interpolated on COSMO grid • Domain: ASRB (Alpine Surface Radiation Budget) network • Daily averages • 10 stations mostly in the Swiss Alps • Gridpoint to surface station association: neighbouring gridpoint chosen Monthly mean SIS-DEM, December 2004 [B. Dürr] Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 3

Radiation validation: Alpine Surface Radiation Budget (ASRB) network ASRB network consists of 10 sites

Radiation validation: Alpine Surface Radiation Budget (ASRB) network ASRB network consists of 10 sites (status October 2006) Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 4

ASRB station Gornergrat, 3110 m asl Photo: Rolf Philipona, Meteo. Swiss Verification of radiation

ASRB station Gornergrat, 3110 m asl Photo: Rolf Philipona, Meteo. Swiss Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 5

July 2006 Global radiation: daily averages (sun elevation > 5°) Mean error -Verification with

July 2006 Global radiation: daily averages (sun elevation > 5°) Mean error -Verification with MSG Comparison with MSG and ASRB Red crosses: clear sky gridpoints & pixels Error bars: stdev errors no bias for clear sky conditions in Summer, but clouds too less opaque (clouds too transparent) Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 6

Cloudiness verification with SYNOP Summer 2006 : bias for +63. . +72 h Pirmin

Cloudiness verification with SYNOP Summer 2006 : bias for +63. . +72 h Pirmin Kaufmann, Meteo. Swiss Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 7

Cloudiness verification with ANETZ Summer 2006 : mean diurnal cycle Mean diurnal cycle bias

Cloudiness verification with ANETZ Summer 2006 : mean diurnal cycle Mean diurnal cycle bias / std dev / rms Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 8

December 2006 Global radiation: daily averages (sun elevation > 5°) Mean error -Verification with

December 2006 Global radiation: daily averages (sun elevation > 5°) Mean error -Verification with MSG Comparison with MSG and ASRB Red crosses: clear sky gridpoints & pixels Error bars: stdev errors negative bias for clear sky conditions in Wintertime Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 9

December 2006: only pixels with fog Global radiation: daily averages (sun elevation > 5°)

December 2006: only pixels with fog Global radiation: daily averages (sun elevation > 5°) Mean error -Verification with MSG positive bias at pixels with fog Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 10

24. 12. 2006 12 UTC MODIS Verification of radiation with MSG & ASRB: Matteo

24. 12. 2006 12 UTC MODIS Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 11

global radiation: hourly values April 06 – March 07 for clear sky conditions in

global radiation: hourly values April 06 – March 07 for clear sky conditions in COSMO-7 & ANETZ Vanessa Stauch, Meteo. Swiss Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 12

downward longwave radiation: Payerne @ 23 UTC clear-sky cases 1999 -2001: COSMO-7 and MODTRAN

downward longwave radiation: Payerne @ 23 UTC clear-sky cases 1999 -2001: COSMO-7 and MODTRAN vs ASRB 84 clear-sky nights 54 cases Dürr et. al. , 2005: Meteorol. Z. , 14, 47 -55 Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 13

Downward longwave radiation: five COSMO-2 runs Winter 06/07 with subgrid topographic corrections without topographic

Downward longwave radiation: five COSMO-2 runs Winter 06/07 with subgrid topographic corrections without topographic corrections Mean error - Verification with ASRB Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 14

Summary • Global radiation: • no bias for clear sky conditions in summertime, but

Summary • Global radiation: • no bias for clear sky conditions in summertime, but clouds too less opaque, resp. too transparent • negative bias for clear sky conditions in wintertime • In wintertime positive bias at pixels with fog • Longwave radiation • Negative bias for clear sky conditions in wintertime Verification of radiation with MSG & ASRB: Matteo Buzzi [presented by Francis Schubiger] 15