Operational cloud-motion winds from Meteosat infrared images

Abstract

This paper describes the operational method of deriving cloud-motion winds (CMW) from the IR images (10.5-12.5 μm) of the European geostationary Meteosat satellites. The method is automatic, that is, the cloud tracking uses cross correlation and the height assignment is based on satellite observed brightness temperature and a forecast temperature profile. Semitransparent clouds undergo a height correction based on radiative forward calculations and simultaneous radiance observations in both the IR and water vapor (5.7-7.1 μm) channel. Cloud-motion winds are subject to various quality checks that include manual quality control as the last step. Typically about 3000 wind vectors are produced per day over four production cycles. This paper documents algorithm changes and improvements made to the operational CMWs over the last five years. -from Authors