Thermal Radiation Down-welling Long-wave Fluxes at the Surface Isabel F. Trigo Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt MSG-based Radiation Products Down-welling Long-wave Flux (DSLF) Definition Algorithm Basis The LSA SAF DSLF product from MSG Validation Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Radiation Budget Solar Radiation Thermal Radiation Earth Surface 30% Short-Wave Net Radiation • Loss • Gain ? 23% 90% Long-Wave Net Radiation 4% • Loss 47% • Gain ? Adapted from K. Trenberth, J. Fasullo, and J. Kiehl. Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Radiation Budget Solar Radiation Thermal Radiation Earth Surface 30% Short-Wave Net Radiation • Loss X 23% Gain 23% 90% Long-Wave Net Radiation 4% 7% Loss • Gain X Adapted from K. Trenberth, J. Fasullo, and J. Kiehl. Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation Down-welling Long-wave Fluxes at the Surface Long-wave Radiation reaching the Surface: Essentially emitted by the lowest 100 m of the atmosphere Emitted by the atmosphere, Ra It is controlled by concentration of abosrbing gases CO2, CH4, H2O, ... Reflected by the surface, Rrefl Emitted by the surface, Rsup presence of clouds, clouds phase temperature profile & temperature of cloud base .... Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation Total irradiance at the surface within the [4 – 100 m] interval: FLW = E d Spectral irradiance emitted downwards by the atmosphere 2 100 1 4 Observed Downward Spectra Radiance – a clear sky day 20 15 12.5 10.5 9 Wavelength (m) Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal 8 7 (adapated from Turner et al., 2004 in J. Atmos. Sci. Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation Remote Sensing Satellite observations provide information on variables that control Down-welling Longwave Fluxes at the surface: Clouds Temperature Profiles Humidity profiles Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal 7 Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation FLW as estimated in the LSA SAF from MSG/SEVIRI Down-welling Longwave Flux at the Surface (DSLF) SEVIRI/MSG Data: SEVIRI/MSG Channel 1 VIS 0.6 m Channel 2 VIS 0.8 Channel 3 NIR 1.6 Channel 4 MIR 3.9 Channel 5 WV 6.2 Channel 6 WV 7.3 Channel 7 IR 8.7 Channel 8 IR/O3 9.7 Channel 9 TIR 10.8 Channel 10 TIR 12.0 Cloud identification: channels 1-4, 7, 9 & 10 Other Information: atmosphere screen temperature (ECMWF forecast) total column water vapour (ECMWF forecast) Channel 11 IR/CO2 13.4 Channel 12 HRV Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation FLW as estimated in the LSA SAF from MSG/SEVIRI Down-welling Longwave Flux at the Surface (DSLF) Parameterization based on Stefan-Boltzman Law: DSLF Tclear-sky , clear-sky 4 n clearskyTclearsky 4 (1 n) cloudyskyTcloudysky Tcloudy-sky , cloudy-sky Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Cloud cover fraction Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation FLW as estimated in the LSA SAF from MSG/SEVIRI Down-welling Longwave Flux at the Surface (DSLF) Parameterization based on Stefan-Boltzman Law: Fractio n of Cloud 4 DSLF skyTsky nDSLFcloudy (1 n)DSLFclear sky m w w 1 1 exp 10 10 Forecasts: (ECMWF) Tsky T2 Td2 2m air temperature Total column water vapour Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 2m dew point depression Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation 15 November 2011 00 UTC 12 UTC Cloud’s signature? Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation 15 November 2011 00 UTC Clear Sky - 12 UTC Cloudy/Partially Cloudy - Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation Generation Frequency - 30 min MSG projection & resolution Over land ... Available since Europe – Feb 2005 Full disk – Jul 2005 But ... Algorithm changed in 2008! Also distributed with quality flag (pixel by pixel basis) Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt Surface Down-welling Long-Wave Radiation Daily Accumulated Long-wave Flux MSG projection & resolution Over land ... Available since Full disk 2010 Also distributed number of time-slots used for each (pixel) estimation. Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt DSLF - Validation Comparison with in situ measurements Comparison with other satellite products (CERES onboard Aqua and Terra) Location of Ground Observations Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt DSLF - Validation LSA SAF DSLF colocated in space and time with Ground Stations & CERES (http://aqua.nasa.gov/about/instrument_ceres.php) Northern Europe Stations Jan 2006 - Apr 2007 clear sky cloudy CERES SEVIRI DSLF Bias RMSE Bias RMSE Clear Sky -0.0 12.7 -2.2 22.3 All Sky -2.1 23.5 3.1 25.3 Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Problems: - Cloud identification at the edge of Meteosat disk - DSLF model for ice clouds - Temperature inversions Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt DSLF - Validation LSA SAF DSLF colocated in space and time with Ground Stations & CERES (http://aqua.nasa.gov/about/instrument_ceres.php) Central Europe Stations Jan 2006 - Apr 2007 CERES SEVIRI DSLF Bias RMSE Bias RMSE Clear Sky -0.9 13.4 0.8 14.5 All Sky -1.4 22.7 1.6 22.5 Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Problems: - Temperature inversions Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt DSLF - Validation LSA SAF DSLF colocated in space and time with Ground Stations & CERES (http://aqua.nasa.gov/about/instrument_ceres.php) Semi-arid & Desert Stations Jan 2006 - Apr 2007 CERES SEVIRI DSLF Bias RMSE Bias RMSE Clear Sky 13.0 26.8 -4.4 14.1 All Sky 17.5 29.6 -5.4 16.9 Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Problems: - Impact of high aerosol loads Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt DSLF LSA SAF estimates DSLF at the original satellite resolution (3 km at the sub-satellite point), every 30 –minutes, covering Meteosat disk Satellite data provide Cloud information Comparison with in situ data -10 Wm-2 < Bias < 10 Wm-2 Root Mean Square Differences (RMS) ranges from considerably (from ~15 to 25 Wm-2) Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt DSLF DSLF Applications – Please see presentation in Session 8 As one of the components of the Surface Radiation Budget, DSLF applications include: Forcing of Land Surface (and Hydrology) models Model Assessment (surface and atmospherirc) Case Studies Ministério da Educação e Ciência Instituto de Meteorologia, I. P. Rua C – Aeroporto de Lisboa 1749-077 Lisboa – Portugal Tel.: (351) 21 844 7000 Fax: (351) 21 840 2370 e-mail: [email protected] URL: http://www.meteo.pt
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