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Arjan van Dijk, Peter den Outer and Harry Slaper One year of OMI, FMI, Helsinki, Finland, June 24-27, 2008. European ground-based UV-measurements used for assessment of OMUVB data quality. Our plan:. Compare the OMUVB product from overpass data with UVB ground measurements - PowerPoint PPT Presentation
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European ground-based UV-measurements used for assessment
of OMUVB data quality
Arjan van Dijk, Peter den Outer and Harry SlaperOne year of OMI, FMI, Helsinki, Finland, June 24-27, 2008
2OMIVAL-2008 E-mail: [email protected]
Our plan:
• Compare the OMUVB product from overpass data with UVB ground measurements
• Check for forms of bias (clouds, latitude, etc…)• Use our own AMOUR-model to estimate UVB from
OMI ozone and OMI reflectivity• Use these AMOUR UVB estimates to assess possible
attributions for the bias in the OMUVB product
3OMIVAL-2008 E-mail: [email protected]
Ground measurements:
Location Lon Lat UV Ozone Pyranometer Sodankyla 26.63 67.64 1991-2006 1978-2006 1957-2006 Jokioinen 23.50 60.81 1995-2006 1978-2006 1957-2006 Norrkoping* 16.15 58.58 1983-2003 1983-2006 1983-2006 Bilthoven 5.18 52.10 1994-2008 1973-2008 1965-2008 Lindenberg 14.12 52.21 1995-2007 1964-2007 1981-2006 Potsdam 13.08 53.36 1995-2003 1964-2003 1937-2003 Hradec Kralove* 15.83 50.19 1996-2006 1964-2006 1953-2006 Thessaloniki* 22.97 40.52 1992-2006 1982-2006 1980-2006 Uccle 4.36 50.80 1993-2006 1973-2008 1951-2006
8OMIVAL-2008 E-mail: [email protected]
Attempts to assess cloud correction
Other satellite,our algorithm:
“the good old times”
OMUVBproduct
Our algorithmon OMI ozone
and OLD OMI reflectivity
(gridded)
Our algorithmon OMI ozone
and NEW OMI cloud
radiative fraction(overpass)
Site: Bilthoven
11OMIVAL-2008 E-mail: [email protected]
Latitude dependence of ratio OMUVB/Measured
“AMOUR_Local” uses:our algorithm + OMI ozone
+ new cloud product as if it were CMF from pyranometer+ site-info for aerosols and
albedo!
12OMIVAL-2008 E-mail: [email protected]
Latitude dependence of ratio OMUVB/Measured
“AMOUR_Local” shows the potential of OMI products!
13OMIVAL-2008 E-mail: [email protected]
Conclusions
• For Europe, OMUVB gives overestimates• Overestimation is strongest in very clouded situations• The new “cloud reflection factor” behaves as a
pyranometer CMF• OMUVB has a latitude-dependent bias • With site-info for aerosols and albedo, we have shown
major improvement of (the bias in) OMI-UVB estimates• Please, resurrect the old-style reflectivity product!• Overpass data (ozone and reflection) and gridded data
seem not in agreement
14OMIVAL-2008 E-mail: [email protected]
• Thank you very much for your kind permission to use the following ground measurements (collected for SCOUT-O3):
Finland:Jussi Kaurola, Anders Lindfors (Jokioinen, Sodankyla)
Greece: Alkis Bais, Andreas Kazantzidis (Thessaloniki)
Czech Republic: Michael Janouch (Hradec Kralove)
Germany: Uwe Feister (Lindenberg, Potsdam)
Sweden: Weine Josefsson (Norrkoping)
Belgium: Didier Gillotay, Hugo de Backer (Ukkel)
