ASSESSMENT OF AGRICULTURAL DROUGHT USING REMOTE SENSING BASED ON MODIS NDVI FOR DIFFERENT AGRO-CLIMATIC ZONES OF TAMIL NADU, INDIA

The State of Tamil Nadu has been located in the Southernmost part of India and experienced the worst drought in the year 2016 due to the failure of North East Monsoon (NEM). Many attempts were made at a different level over Tamil Nadu for drought analysis, but none of the studies have been conducted in detail to assess the aspects of drought at the agro-climatic zones (ACZ) level. This study conducted a comprehensive drought assessment for the NEM seasons (October–December) of the years 2015, 2016 and 2017 by using Normalized difference vegetation index (NDVI) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) across Tamil Nadu for seven ACZ viz., North-Eastern, North-Western, Western, High-Altitude and Hilly, Cauvery Delta, Southern zone and High Rainfall Zones. The MOD13A1 product was covered entire study area by 16-day composite product tiles (h25v07 and h25v08) at 500 m spatial resolution. The range of NDVI values obtained and five classes were considered viz., <0, 0.0 – 0.2, 0.2 – 0.4, 0.4 – 0.6 and > 0.6 representing no vegetation, barren, stressed, good, and very good condition have been classified, respectively. The results show that the total cropped area of Tamil Nadu during North-East Monsoon, 2015 an area of 71150 ha was delineated under the stressed class which accounted for 0.76 percent whereas, good and very good were found to be 22.96 and 76.12 percent, respectively according to the NDVI classes. Among the agro-climatic zones, North-Eastern Zone registered the largest area of 38200 ha under stressed condition followed by the Southern zone with an area of 14575 ha. For 2016 NEM season, In total, an area of 460975 ha was delineated under the stressed class which accounted for 4.91 percent whereas, good and very good classes were found to be 47.76 and 47.28 percent whereas Southern Zone registered the largest area of 160500 ha under stressed condition followed by Western zone with an area of 149200 ha. Finally for 2017 NEM, In total, an area of 460975 ha was delineated under the stressed class which accounted for 0.49 percent whereas, good and very good were found to be 12.05 and 87.40 percent of total cropped area and Southern zone registered the largest area of 34850 ha under stressed condition followed by Cauvery Delta zone with an area of 7700 ha. The seasonal NDVI pattern during the years 2015 to 2017 was significantly different and it indicated that the date of sowing depends on the arrival of the monsoon and thereby the NDVI profile patterns shifts accordingly.