Cloud Physical Properties Based Precipitation Products for Weather and Climate Applications
Rob Roebeling presents the concept and the applicability of the method developed at KNMI to calculate precipitation occurrence and intensity from cloud physical properties retrieved from passive imager satellite data onboard geostationary satellites.
Length: 30 min
Author: Rob Roebeling (EUMETSAT)
This lecture presents the concept, the validity, and the applicability, of the method developed at the Royal Netherlands Meteorological Institute (KNMI) to calculate precipitation occurrence and intensity from cloud physical properties retrieved from passive imager satellite data onboard geostationary satellites.
A brief introduction will be given on the concept of the cloud physical properties retrievals and the precipitation retrievals, as well as an underpinning why cloud physical properties are pre-eminently suitable for quantitative precipitation retrievals. The validity of the precipitation retrievals will be demonstrated for Europe (and Africa), using weather radar and gridded rain-gauge data to perform a triple-collocation statistical evaluation. For this evaluation, the precipitation retrievals are derived using the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard Meteosat Second Generation satellites, the weather radar data are obtained from the common European integrated weather radar system, and the gridded rain gauge observations are obtained from the Global Precipitation Climatology Centre (GPCC) and/or the European Climate Assessment and Data set (ECA&D). The spatial and temporal dependence of the respective errors are presented and discussed.
The results suggest that the gridded rain-gauge datasets agree very well with the precipitation retrievals from SEVIRI, while they agree weakly with the weather radar observations. Part of these differences is caused by the fact that the weather radar products are based on different radars and algorithms, whereas the precipitation retrievals from SEVIRI have the advantage to be based on a single instrument. Since observations from single weather radar can be used to determine temporal variations in precipitation it is concluded that these observations are best suited for studying the diurnal or seasonal variations at a local scale.
The lecture will conclude with some examples for using the precipitation retrievals from SEVIRI for specific weather and climate applications.