1. SURFACE SOLAR IRRADIANCE FROM SEVIRI SATELLITE DATA
Wouter Greuell, Jan Fokke Meirink and Ping Wang
Royal Netherlands Meteorological Institute (KNMI)

2. 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

3. 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

4. SOME REMARKS Global, direct and diffuse irradiance
Algorithm is physics-based

5. 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

6. 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

7. VALIDATION WITH BSRN Baseline Surface Radiation Network
Lerwick
Toravere
Cabauw
Lindenberg
Camborne
Payerne
Palaiseau
Carpentras
Sede Boqer
Hourly means

8. CLEAR SKY DIRECT, MACC INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct
Carpentras, direct

9. CLEAR SKY GLOBAL, MACC INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global
Carpentras, global

10. ALL SKY DIRECT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct
Carpentras, direct

11. ALL SKY GLOBAL
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global
Carpentras, global

12. SNOW ALL SKY
Lindenberg, global
Toravere, global

13. MAP NETHERLANDS
2006, global irradiance
, precipitation

14. MAP IBERIAN PENINSULA

15. 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

18. 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

19. CLEAR SKY DIRECT, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct
Carpentras, direct

20. CLEAR SKY DIFFUSE, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, diffuse
Carpentras, diffuse

21. CLEAR SKY GLOBAL, AERONET INPUT
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global
Carpentras, global

22. WATER CLOUDS GLOBAL
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global
Carpentras, global

23. ALL SKY GLOBAL
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global
Carpentras, global

24. 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

25. HIGH SOLAR ZENITH ANGLES
Cabauw, global
Lindenberg, global

26. DEPENDENCE ON COT, REFF, SZA

27. 10 YEARS MODIS ALBEDO
Visual
Near-infrared

28. COMPARISON IN-SITU DATA
Red: coastal stations
Blue: other stations

30. CLEAR DIRECT, MONTHLY AERONET
green = spring, blue = summer, red = autumn, black = winter
Cabauw, direct
Carpentras, direct

31. CLEAR GLOBAL, MONTHLY AERONET
green = spring, blue = summer, red = autumn, black = winter
Cabauw, global
Carpentras, global

32. 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