In May 1999, India launched IRS-P4 (OCEANSAT-I) satellite with two payloads i.e. Multi-frequency Scanning Microwave Radiometer (MSMR) and an Ocean Color Monitor (OCM) to study both the biological and physical parameters of the oceans. It completes fourteen and half revolutions around the globe per day in a sun-synchronous orbit at an altitude of about 720 Km. and it provides an observational swath width of 1360 Km. The MSMR sensor is configured as an eight channel radiometer using four frequencies with both vertical and horizontal polarizations. Surface wind speed and total precipitable water content are among the main geo-physical parameters derived at 75Km and 150Km resolutions.

At National Centre for Medium Range Weather Forecasting (NCMRWF), India, suitable schemes have been developed to utilize the processed meteorological data from MSMR in the Global Data Assimilation System at T80L18 resolution. The MSMR wind speed and the total precipitable water content, derived at 75 Km. resolution have been assimilated at NCMRWF along with other global meteorological data received on operational basis during May to September 2000. Immediate impact of the MSMR data is to make the analyzed atmosphere more moist compared to the operational analyses. The monsoon circulation is better defined in the new analyses. Results of a comparative examination of these two sets of analyses (viz. operational analyses and analyses with MSMR data) will be presented in the symposium.