Estimation of Indian summer monsoon rainfall using

Authors: Satya Prakash C Mahesh R M Gairola P K Pal

Publish Date: 2010/12/01

Volume: 110, Issue: 1-2, Pages: 45-57

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Abstract

In the present study an attempt has been made to estimate and validate the daily and monthly rainfall during the Indian summer monsoon seasons of 2008 and 2009 using INSAT Indian National Satellite System Multispectral Rainfall Algorithm IMSRA technique utilizing Kalpana1 very high resolution radiometer VHRR measurements In contrary to infrared IR microwave MW rain rates are based on measurements that sense precipitation in clouds and do not rely merely on cloud top temperature Geostationary satellites provide broad coverage and frequent refresh measurements but microwave measurements are accurate but sparse IMSRA technique is the combination of the infrared and microwave measurements which make use of the best features of both IR and MWbased rainfall estimates The development of this algorithm included two major steps a classification of rainbearing clouds using proper cloud classification scheme utilizing Kalpana1 IR and water vapor WV brightness temperatures Tb and b collocation of Kalpana1 IR brightness temperature with Tropical Rainfall Measuring Mission TRMMPrecipitation Radar PR surface rain rate and establishment of a regression relation between them In this paper the capability of IMSRA as an operational algorithm has been tested for the two monsoon seasons 2008 and 2009 For this IMSRA has been used to estimate daily and monthly rainfall and has been intercompared on daily and monthly scales with TRMM Multisatellite Precipitation Analysis TMPA3B42 V6 product and Global Precipitation Climatology Project GPCP rain product during these two monsoon years The daily and monthly IMSRA rainfall has also been validated against groundbased observations from Automatic Weather Station AWS Rain Gauge and Buoy data The algorithm proved to be in good correlation with AWS data over land up to 070 for daily rain estimates except orographic regions like NorthEast and SouthWest India and 072 for monthly rain estimates The validation with Buoys gives the reasonable correlation of 049 for daily rain estimates and 066 for monthly rain estimates over Tropical Indian OceanWe thank Director Space Applications centre for the encouragements for the research work carried out in the present study The TMPA3B42 and GPCP data from TRMM Online Visualization and Analysis System TOVAS RAMA Buoy data from Pacific Marine Environmental Laboratory PMEL and Kalpana1 data and AWS data provided by MOSDAC are thankfully acknowledged

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