Satellite meteorology

255-259The uses of data from meteorological and oceanographic satellites for meteorology are described briefly in this overview paper. Distinguishing between operational and experimental (R&D) uses, emphasis is placed on the latter, with a view to bringing some current and outstanding research problems to the notice of University and Research Institutes. Operational uses are very briefly touched upon. Research efforts are further subdivided into those using data from operational MET-SATS (INSAT, NOAA) which would be more easily accessible by Universities, and those using data from experimental satellites (e.g. ERS-1 and DMSP) where only limited data sets may be available. Developing applications from these later type of satellites, may lead to a demand for similar Indian satellites. The INSAT and NOAA data are being deployed to obtain useful input towards the forecast models such as divergence/vertical velocity field, sea-surface wind in sun-glitter area, air-sea heat exchanges, cloud height and thickness, aerosol optical depth over oceans and soil moisture on large scale. Indicators helpful in monsoon onset prediction and seasonal rainfall forecast have been obtained from NOAA soundings. Cyclone track prediction methods are being developed from INSAT data, whereas intensity is quantified from NOAA 300 mbar temperature. The experimental satellite DMSP with its sensor SSM/I has been used for improving precipitation estimate which, in turn, could feed to medium range weather models as a heat input. Surface winds and humidity from SSMII along with SST from NOAA yielded evaporation (latent heat exchange) estimates over oceans. The ERS-l scatterometer has been used to obtain realistic wind vector fields over oceans. In the specific case of a cycione, the rotating winds and the centre of the cyclone could be detected from scatterometer data. The 'along track scanning radiometer' (ATSR) on ERS provides improved SST besides cloud height. The upper atmospheric research satellite (UARS) is meant for observing stratospheric/thermospheric minor constituents, but in as much as they influence tropospheric weather, the data may be considered relevant to meteorology. Finally it is suggested that, preparatory work is called for, to make optimal use of future INSAT-2E (e.g. optical CCD and water channel) and future NOAA (improved sounders)