delineation of drought prone regions over tamil nadu through agrometeorology and space based observations

Abstract

ABSTRACT newlineDELINEATION OF DROUGHT PRONE REGIONS OVER TAMIL NADU newlineTHROUGH AGROMETEOROLOGY AND SPACE BASED OBSERVATIONS newlineBy newlineM. VENGATESWARI newlineI.D.No. 2016801006 newlineDegree : Doctor of Philosophy in Meteorology newlineChairperson : Dr. V.GEETHALAKSHMI, Ph.D. newlineDirtector newlineDirectorate of Crop Management newlineTamil Nadu Agricultural University newlineCoimbatore - 643 003 newline2019 newlineA study was carried out at the Agro Climate Research Centre, Tamil Nadu newlineAgricultural University, Coimbatore in the academic year 2017-2019 to assess drought newlinefrequency and spatial spread for drought over historical time period (1981 2017) and newlinefuture time slice such as near century (2010-2039), mid-century (2040-2069) and end newlineof century (2071-2099) using drought indices. Impact of drought on crops was newlineassessed using crop simulation model and vegetation index. Vulnerable areas for newlinedrought over Tamil Nadu was identified using the dynamically downscaled output newlineobtained from the GCM (CCSM 4) under RCP 4.5 and RCP 8.5 scenario .through the newlineregional climate model RegCM 4.4 and suggesting alternative cropping system for newlinesustainable crop production. newlineGood agreement between the reanalyzes climate data with the observed maximum newlineand minimum temperature as well as rainfall over all the zones of Tamil Nadu except High newlinerainfall and Hilly zone. Among the data sources for rainfall, TRMM is able to capture the newlinerainfall data well. The maximum and minimum temperature over the Tamil Nadu are newlineprojected to increase all the time slice under both RCP 4.5 and 8.5 (CCSM4). Annual newlineand SWM rainfall is expected to increase in future with varied magnitude. NEM rainfall newlinein future would increase in near and mid-century, while decrease in the end century for newlineRCP 4.5 scenario. However, decrease is expected in all time slices under RCP 8.5 newlinescenario. newlineFrequency of drought was higher in Southwest monsoon compared to newlineNortheast monsoon. Based on the projections of rainfall deviation, the area that will get newlineexposed to drought would reduce in the future. Based on SPI, drought occurrence is newlineexpected to