Catchment-level agricultural drought hazard vulnerability analysis of Ganga Basin (India) using spectral indices

The Gangetic Plains (GP) comprising India’s food belt and extending over an area of eight lakh square kilometres (8, 35,475 km2) witness recurrent drought which affects food production owing to climate change sensitivity of the region. Agricultural drought vulnerability analysis has been attempted in the present study over the past 19 years to understand the trend of drought and distribution across the specified spatiotemporal spectrum, based on satellite-based drought indices computation viz. Vegetation Condition Index (VCI), Temperature Condition Index (TCI), and Vegetation Health Index (VHI) with the help of Moderate Resolution Imaging Spectroradiometer (MODIS), Normalized Difference Vegetation Index (NDVI) and land surface temperature (LST) data. The results revealed that the basins with high vulnerability are concentrated in the south-western GP exhibiting low values of VHI in contrast to dominantly higher values in the rest of the GP making it very much vulnerable. 15.62% of GP faced extreme to severe drought vulnerability followed by 16.65% moderate vulnerability. Precipitation data from Tropical Rainfall Measuring Mission (TRMM) used for future prediction using Sen’s slope method revealed an increasing trend in western GP up to + 40 mm/year while a decreasing trend in the eastern GP up to − 40 mm in yearly accumulated rainfall. The future prediction of temperature showed similar trend as precipitation with a magnitude of 0 to 0.05 °C increase yearly. With the probability of rainfall increasing in the near future, certain water-harvesting structure construction in the western region can ensure good water supply to the crops grown here making them less vulnerable.