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Derivation of Water Vapor Winds (WVWs) using water vapor channel (5.7 μm-7.1 μm) of Very High Resolution Radiometer (VHRR) payload onboard India’s KALPANA-1 geostationary meteorological satellite started in March, 2008 on a routine operational basis at India Meteorological Department (IMD), New Delhi using upgraded INSAT-2E meteorological data processing system of IMD. Recently a modification has been introduced in the algorithm used for derivation of this product. The primary change introduced is making use of first guess forecast fields obtained from National Center for Environmental Prediction (NCEP) Global Forecast System (GFS), at a resolution of 1º× 1º instead of forecasts of operational Limited Area Model (LAM) of IMD. In the present study, the quality check of operational WVWs has been carried out using ECMWF Model forecast data, covering the area 40ºE-129ºE and 40ºS-40ºN. Results show a significant increase in the number of good quality WVWs. The RMSE of KALPANA-1 derived WVWs, as compared to ECMWF first guess forecast field has improved to 5 m/s which are generally comparable with the similar results of other geostationary meteorological satellites in the world. Finally, these WVWs of improved quality are transmitted on GTS for operational use by the end users in both SATOB as well in BUFR formats.

Detailed error analysis has also been carried out for validation of WVWs using collocated radiosonde observations for the period from May 2008 to July 2009 and the available mid-upper level winds derived from European METEOSAT-7 data for the period from October to December 2008. The analysis …