Evaluating the utility of normalized difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI) for monitoring drought in Bolangir district of Odisha

A single index is insufficient to fully describe the multi-scale, multi-impact nature of drought in all its complexity. Hence, all research efforts on drought monitoring and assessment are directed towards developing a composite index through appropriate blending techniques. In order to make it acceptable by a wider section of drought management, the information of drought also needs to be put in simpler terms. The present study attempts to evaluate the performance of two remote sensing drought monitoring indices namely Normalized Difference Vegetation Index (NDVI) and Vegetation Condition Index (VCI) in monitoring the drought conditions in Bolangir district of Odisha. In the present study the NDVI deviation and VCI were derived from NDVI data based on the methodology given in ‘Manual for Drought Management 2016’and both indices were compared on the basis of their capability of identifying drought conditions in the blocks of Bolangir. The results indicated that the impact of early season drought was identified by VCI was more as compared to NDVI deviation, which had reflected that VCI is a good indicator than NDVI. However, care must be taken using VCI for monitoring drought because it is not highly correlated with station based meteorological drought indices and it is strongly influenced by spatially varying environmental factors. Both NDVI and VCI can be used along with other rainfall, agriculture, soil moisture and hydrology drought indices for assessment of intensity of drought.