SURFACE SOLAR IRRADIANCE FROM SEVIRI SATELLITE DATA Wouter Greuell, Jan Fokke Meirink and Ping Wang Royal Netherlands Meteorological Institute (KNMI)
Jan 11, 2016
SURFACE SOLAR IRRADIANCE FROM SEVIRI SATELLITE DATAWouter Greuell, Jan Fokke Meirink and Ping WangRoyal Netherlands Meteorological Institute (KNMI)
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
SICCS: SURFACE INSOLATION IN CLOUDY
CONDITIONS FROM METEOSAT SEVIRI IMAGERY - ALGORITHM
Measured radiances
attwo
wavelengths
Cloudproperties
SurfaceSolar
Irradiancefor
broadband
narrowbandRTM
broadbandRTM
Cloudmask
for clearpixel
forcloudypixel
Aerosolproperties,
Surfaceelevation
broadbandRTM
SOME REMARKS
• Global, direct and diffuse irradiance
• Algorithm is physics-based
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
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
VALIDATION WITH BSRNBaseline Surface Radiation Network
Cabauw
Toravere
Payerne
Carpentras
Sede Boqer
PalaiseauCamborne
Lerwick
Lindenberg
Hourly means - 2006
CLEAR SKY DIRECT, MACC INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct Carpentras, direct
CLEAR SKY GLOBAL, MACC INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global Carpentras, global
ALL SKY DIRECT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct Carpentras, direct
ALL SKY GLOBAL
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global Carpentras, global
SNOW ALL SKY
Lindenberg, global Toravere, global
MAP NETHERLANDS2006, global irradiance
1981-2010, precipitation
MAP IBERIAN PENINSULA
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 resolutionbased on physicsability to deal with snowalbedo background map
Weak points:limited to METEOSAT disccoastal regionsrelief effects not considered
Data will be made available for user on the Internet
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
CLEAR SKY DIRECT, AERONET INPUTgreen = spring, blue = summer, red = autumn, black = winter
Cabauw, direct Carpentras, direct
CLEAR SKY DIFFUSE, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, diffuse Carpentras, diffuse
CLEAR SKY GLOBAL, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global Carpentras, global
WATER CLOUDS GLOBAL
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global Carpentras, global
ALL SKY GLOBAL
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global Carpentras, global
TABLE BIASES
BSRN stationClear sky
BSRNClear 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 +0.015 +0.016
Toravere -0.003 +0.007 +0.017 +0.039 +0.025 +0.020
Note: ice cloud transmissivity was corrected by -0.0375
Transmissivities
HIGH SOLAR ZENITH ANGLES
Cabauw, global Lindenberg, global
DEPENDENCE ON COT, REFF, SZA
10 YEARS MODIS ALBEDOVisual Near-infrared
COMPARISON IN-SITU DATA
Red: coastal stations
Blue: other stations
CLEAR DIRECT, MONTHLY AERONET
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct Carpentras, direct
CLEAR GLOBAL, MONTHLY AERONET
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global Carpentras, global
OTHER INPUT
Measured radiances
attwo
wavelengths
Cloudproperties
SurfaceSolar
Irradiancefor
broadband
narrowbandRTM
broadbandRTM
Cloudmask
for clearpixel
forcloudypixel
Aerosolproperties,
Surfaceelevation
broadbandRTM
H2O,surfacealbedo,
SZA
H2O, surfacealbedo, SZA