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Comparison of GOME-2 and OMI surface UV products. Niilo Kalakoski, Finnish Meteorological Institute. O3M SAF Offline UV Product. Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF)
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Comparison of GOME-2 and OMI surface UV products Niilo Kalakoski, Finnish Meteorological Institute
O3M SAF Offline UV Product • Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) • Joint effort of 10 institutes in 7 European countries, FMI is the leading entity • Part of EUMETSAT’s Polar System (EPS) ground segment • 3 Metop satellites to cover some 15 years up to 2020 • Metop-A was successfully launched 19 October 2006 • Ozone, trace gases and aerosols from GOME-2 • Offline Surface UV (OUV) Product: • Developed and processed at FMI • Contains • Daily (integrated) doses • Daily maximum dose rates • Biological weightings: • Erythemal (CIE) • DNA damage • Generalized Plant Response • SCUP-h • 0.5 x 0.5 degree grid, HDF5 format • Currently demonstrational status
O3M SAF OUV: Inputs • Inputs: Total Ozone • GOME-2 NRT Total Ozone (NTO) product • Produced by the German Aerospace Center (DLR) within the O3M SAF • Read from EUMETCast broadcasting, 2.5 hours from sensing • Used in modelling of surface UV irradiance and AVHRR channel 1 reflectance • Inputs: Surface albedo: • Static regions (no seasonal variability): • TOMS 380 nm MLER • Dynamic regions (seasonal snow or ice): • Climatology of A. Tanskanen • Inputs: Aerosols: • Currently: Global Aerosol Dataset GADS • Testing with Aerocom climatology
O3M SAF OUV: Cloud Optical Depth Data • Inputs: AVHRR ch. 1 (630 nm) reflectances • exploits the synergy between Metop and NOAA satellites • Data readily available from EUMETCast • At least 2 cloud observations per day obtained globally • Morning (9:30): Metop-A • Afternoon (14:30): NOAA-18 • Using both morning and afternoon observations improves the daily dose integration • Currently no cloud retrieval if • solar zenith angle > 70 degrees • surface albedo > 60 %
Comparisons of OUV and OMIuv • Surface UV radiation in kJ/m2 from OMI (left) and GOME-2 (right) for February 1st 2008. • GOME-2 UV not retrieved for SZA > 70 degrees
Time series of the surface UV from OMI and GOME-2 compared to ground-based measurements • CIE erythemal daily dose • Jokioinen (above) and Sodankylä (below) • August 2007
Scatterplot comparisons of OMIuv and OUV CIE erythemal daily doses • Jokioinen (above) and Sodankylä (below) • From June 1st 2007 to May 31st 2008