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Evaluation and application of SEVIRI rainfall retrievals over West Africa. Erwin Wolters 1 Bart van den Hurk 1,2 Rob Roebeling 1. 1: Royal Netherlands Meteorological Institute (KNMI), de Bilt, Netherlands 2: Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht, Netherlands.
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Evaluation and application of SEVIRIrainfall retrievals over West Africa Erwin Wolters1 Bart van den Hurk1,2 Rob Roebeling1 1: Royal Netherlands Meteorological Institute (KNMI), de Bilt, Netherlands 2: Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht, Netherlands
Motivation Precipitation of great importance to hydrological cycle Precipitation observations sparse over West Africa SEVIRI precipitation algorithm: daytime only Multispectral Based on retrieved cloud physical properties high spatial/temporal resolution
CPP Precipitation Properties algorithm SEVIRI R0.6, R1.6 =f(R0.6 μm) ΔH=f(CTT) re=f(R1.6 μm) CWP=f(,re) PRP=f(CWP,ΔH)
Evaluation: comparison with CMORPH Seasonal evolution (2005) over West Africa Diurnal cycle during daytime (7:30 – 16:30 UTC)
Seasonal cycle 2005 Rainrate CPP-PP CMORPH coastline
Latitudinal cross section May Jul Sep 2005 2006
Daytime cycle June Semi-arid savannah Rain forest
Soil moisture-precipitation interaction • Is rain occurrence and intensity different over wet and dry soils? • -Focus on May (pre-monsoon) and Sep (post-monsoon) • -No rain at 7:30 UTC to avoid nighttime MCS remnants • -Anomalies of previous-day AMSR-E soil moisture, 0.25° × 0.25°
Methodology SEVIRI precipitation class “dry” class “wet” Soil moisture AMSR-E Soil moisture anomalies
Results May and Sep 2005 Rain rate Rain occurrence % mm h-1 % mm h-1
Conclusions/outlook CPP in good agreement with CMORPH (and TRMM-PR) Applicable at various time scales (seasonal, daytime cycle) Unprecedented temporal resolution SEVIRI of added value To be extended with nighttime scheme using WV and IR channels