The Eumetsat Multi-sensor Precipitation Estimate (mpe)

The combination of measurements from different satellite instruments for the estimation of precipitation is a promising way to overcome the shortcomings of measurements from a single data source. EUMETSAT realised the Multi-sensor Precipitation Estimate (MPE) in order to combine the advantages of the high temporal and comparably high spatial resolution of a geostationary IR sensor with the higher accuracy in rain rate retrieval of microwave sensors on polar orbiting satellites. IR-images from METEOSAT 7 on a geostationary orbit at 0° longitude are co-located with passive microwave data from the Special Sensor Microwave/Imager (SSM/I). The retrieval of rain rates from microwave data is based on established algorithms. A statistical matching in temporal and geographical windows is performed in order to correlate the IR brightness temperatures to the retrieved rain rates. The size of the time and space windows is selected to fit the scale of typical synoptic weather systems. The assumption is used that cold clouds are more likely to produce precipitation than warmer clouds, in the same synoptic system. In this way the method reproduces the average rain rates according to the microwave measurements within the time and space window as well as the most likely spatial and temporal distribution of the precipitation in the full resolution of METEOSAT. The MPE algorithm prototype is integrated in EUMETSAT’s Meteorological Product Extraction Facility (MPEF) and will be validated by reprocessing METEOSAT data from the year 2000.