چکیده (انگلیسی):

Drought is one of the major natural hazards affecting the environment and economy of countries worldwide. As a natural hazard, drought is best characterized by multiple climatological and hydrological parameters. An understanding of the relationships between these two sets of parameters is necessary to develop measures for mitigating the impacts of droughts. Droughts are recognized as an environmental disaster and have attracted the attention of environmentalists, ecologists, hydrologists, meteorologists, geologists, and agricultural scientists.. Low rainfall has mainly caused droughts and subsequent reduction in agricultural production. Droughts have been a recurring feature of the Indian climate, therefore, study of historical droughts may help in the delineation of major areas facing drought risk and thereby, management plans can be formulated by the government authorities to cope with the disastrous effects of this hazard. In recent years, Geographic Information System (GIS) and Remote Sensing (RS) have played a key role in studying different types of hazards, either natural or man-made. This paper emphasizes upon the application of RS and GIS in the field of drought risk evaluation. The study area taken is a part of the Jamnagar district of Gujarat between latitude 22°19′46′′N to 22°46′01′′N and longitude 70°20′56′′E to 70°47′34′′E. The study was conducted with satellite images of year 1977, 1990 and 1999. Data has been acquired mainly from two sources, firstly Normalized Difference Vegetation Index (NDVI) obtained from satellite sources and secondly rainfall obtained from ground rainfall stations record. In the present paper, an effort has been made to derive drought risk areas facing agricultural as well as meteorological drought by use of Normalized Difference Vegetation Index (NDVI) from Landsat images. NDVI values reflect the different geographical conditions quite well. The NDVI and rainfall was found to be highly correlated. It is therefore concluded that temporal variations of NDVI are closely linked with precipitation.