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Published byBenjamin McAllister Modified over 11 years ago
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SURFACE SOLAR IRRADIANCE FROM SEVIRI SATELLITE DATA
Wouter Greuell, Jan Fokke Meirink and Ping Wang Royal Netherlands Meteorological Institute (KNMI)
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DATA SET Input: SEVIRI (METEOSAT) cloud mask and cloud properties
Spatial resolution: 3 x 3 km2 at nadir (4 x 7 km2 for NL) Temporal resolution: 4 images / hour From 2004
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SICCS: SURFACE INSOLATION IN CLOUDY CONDITIONS FROM METEOSAT SEVIRI IMAGERY - ALGORITHM
broadband RTM Aerosol properties, Surface elevation for clear pixel Surface Solar Irradiance for broadband Cloud mask for cloudy pixel Measured radiances at two wavelengths Cloud properties broadband RTM narrowbandRTM
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SOME REMARKS Global, direct and diffuse irradiance
Algorithm is physics-based
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INPUT Cloud mask from METEOSAT SEVIRI
Cloud properties (phase, optical thickness and particle size) from METEOSAT SEVIRI Aerosol optical depth from MACC Surface albedo derived from MODIS surface albedo Integrated water vapor from ECMWF
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DIRECT IRRADIANCE FOR CLOUDY SKIES
Plane-parallel assumption does not work Gaps in clouds are crucial On y-axis ratio of Measured direct irradiance by computed clear-sky direct irradiance
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VALIDATION WITH BSRN Baseline Surface Radiation Network
Lerwick Toravere Cabauw Lindenberg Camborne Payerne Palaiseau Carpentras Sede Boqer Hourly means
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CLEAR SKY DIRECT, MACC INPUT
green = spring, blue = summer, red = autumn, black = winter Cabauw, direct Carpentras, direct
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CLEAR SKY GLOBAL, MACC INPUT
green = spring, blue = summer, red = autumn, black = winter Cabauw, global Carpentras, global
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ALL SKY DIRECT green = spring, blue = summer, red = autumn, black = winter Cabauw, direct Carpentras, direct
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ALL SKY GLOBAL green = spring, blue = summer, red = autumn, black = winter Cabauw, global Carpentras, global
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SNOW ALL SKY Lindenberg, global Toravere, global
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MAP NETHERLANDS 2006, global irradiance , precipitation
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MAP IBERIAN PENINSULA
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Data will be made available for user on the Internet
CONCLUSIONS Station mean absolute value of the bias: Direct irradiance: 6 W/m2, 4.1% Diffuse irradiance: 5 W/m2, 3.4% Global irradiance: 7 W/m2, 1.9% Strong points: high temporal and spatial resolution based on physics ability to deal with snow albedo background map Weak points: limited to METEOSAT disc coastal regions relief effects not considered Data will be made available for user on the Internet
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INTERPOLATION OF ALBEDO
From MODIS MCD43C3 Temporal resolution: 8 days Spatial resolution: 0.05 x 0.05 degrees Combination of linear interpolation and mean annual cycle Includes snow and ice
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CLEAR SKY DIRECT, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter Cabauw, direct Carpentras, direct
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CLEAR SKY DIFFUSE, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter Cabauw, diffuse Carpentras, diffuse
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CLEAR SKY GLOBAL, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter Cabauw, global Carpentras, global
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WATER CLOUDS GLOBAL green = spring, blue = summer, red = autumn, black = winter Cabauw, global Carpentras, global
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ALL SKY GLOBAL green = spring, blue = summer, red = autumn, black = winter Cabauw, global Carpentras, global
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TABLE BIASES Transmissivities BSRN station Clear sky BSRN
Clear sky SEVIRI Water clouds Ice clouds All clouds All skies 6 stations -0.001 +0.013 +0.009 -0.003 +0.004 +0.006 Lerwick -0.027 +0.021 +0.020 +0.015 +0.016 Toravere +0.007 +0.017 +0.039 +0.025 Note: ice cloud transmissivity was corrected by
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HIGH SOLAR ZENITH ANGLES
Cabauw, global Lindenberg, global
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DEPENDENCE ON COT, REFF, SZA
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10 YEARS MODIS ALBEDO Visual Near-infrared
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COMPARISON IN-SITU DATA
Red: coastal stations Blue: other stations
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CLEAR DIRECT, MONTHLY AERONET
green = spring, blue = summer, red = autumn, black = winter Cabauw, direct Carpentras, direct
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CLEAR GLOBAL, MONTHLY AERONET
green = spring, blue = summer, red = autumn, black = winter Cabauw, global Carpentras, global
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OTHER INPUT broadband RTM broadband narrowbandRTM RTM H2O, surface
albedo, SZA broadband RTM Aerosol properties, Surface elevation for clear pixel Cloud mask Surface Solar Irradiance for broadband for cloudy pixel Measured radiances at two wavelengths Cloud properties H2O, surface albedo, SZA broadband RTM narrowbandRTM
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