A Customized GIS Application to Create and Analyze Drought Characteristics using Geoinformation Technologies

要旨

In this study, different drought indices have been analyzed with the aim of deriving Normalized Difference Vegetation Index (NDVI), Aridity Index (AI), and Standardized Precipitation Index (SPI) using remotely sensed and meteorological data. The indices are derived using mean temperature, precipitation, vegetation, and evapotranspiration (ET0). MODIS NDVI product for the drought year 2002 and drought free 2005 has been acquired from the archives of GODDARD Space Flight Center. NDVI is used to calculate the vegetation index, AI is computed to analyze the temperature and rainfall, and SPI are calculated to quantify the precipitation deficit. Drought indices are analyzed on monthly basis through spatial maps generated using Geographical Information System and geostatic environment. The study reveals that the state is having diverse drought conditions in 2002 when compared with 2005. Particularly the Rayalaseema region suffers more droughts due to poor and delayed monsoon and insufficient water. Telangana region also has some effect of drought due to abnormal rainfall. The drought is also found in part of north Andhra region. The spatial maps of these indices are customized using MapObjects in Visual Basic Environment (VBE) with user-friendly tools.