IMPACT OF CLIMATIC CHANGE ON DROUGHT USING GEOSPATIAL TECHNOLOGY

Abstract

Drought can be broadly defined as "severe water shortage". Main causes of drought are low rainfall and fall in agricultural production. This study stresses upon the use of RS and GIS in the field of impact of climate change on drought. In the present work, an effort has been made to derive drought risk areas facing agricultural as well as meteorological drought by use of temporal images from LANDSAT TM, ETM+. Correlation and regression analysis was performed between Normalized Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), Difference of Pre and Post monsoon ofNDVI, SAVI of satellites images of Landsat-7 of sensor ETM+ and observed meteorological based drought indices such as Normalized Deviation (ND), De Martonne's Index (IA), Pluvothermic Quotient (PQ), Negative Moisture Index (NMI) in Jodhpur District, where the occurrence is high in Jodhpur District. Vegetation Condition Index (VCI), Temperature Condition Index (TCI), Rainfall Anomaly and Food Grain Anomaly. Standard Precipitation Index (SPI) values were interpolated to get the spatial pattern of meteorological based drought. Crop yield and production trend was plotted and an equivalent NDVI threshold was identified to get the agricultural drought risk. Monthly rainfall data from six stations were used to derive the Standardized Precipitation Index (SPI). The Landsat-7 ETM+ and Landsat-5 TM satellite sensor data was used for calculating Brightness Temperature (BT), Land Surface Temperature (LST). BT was converted to the Vegetation Condition Index (VCI) and the Temperature Condition Index (TCI), which are useful indices for the estimation of vegetation health and drought monitoring. The analysis was carried out for a period of 21 years (1991-2011) and from the SPI analysis it was observed that 2002 was a drought year. On the basis of the satellite-based indices, slope map and elevation map of Digital Elevation map (DEM) of CARTOSAT-1 the study area was divided into drought categories of moderate, mild, no drought and normal condition. It is found that in 2002 all of the area under study was affected by drought with greater intensity, can be classified as extreme and severe drought conditions. Keywords: Drought, NDVI, SAVI, ND, IA, PQ, NMI, SPI, BT, TCI, LST, DEM, Crop yield and Production IV