Drought detection and declaration in India

Abstract

Drought is a complex, multifaceted, and one of the most widespread natural disasters causing an economic loss of billions of dollars. Drought declaration is crucial since it signifies the beginning of states's response to drought. India's current drought management policy is specified in the Manual for Drought Management 2016. While the manual provides comprehensive guidelines to states and regional Drought Monitoring Centres (DMC's) for monitoring and declaration of droughts, assessing the current drought detection framework and its suitability in different regions has been lacking. Using gridded products of precipitation, soil moisture, and remote sensing indicators, we examine the differences between detected and declared droughts for all the districts in India during the 2000-2017 period. Comparison of detected and declared droughts show a higher probability of detection (POD) in central India. In contrast, lower POD was found in regions of high drought susceptibility like Rajasthan, Andhra Pradesh and Karnataka. Large differences between the detected and declared droughts were identified in the irrigated regions of Punjab and Gangetic Plain. The use of Solar-induced chlorophyll Fluorescence (SIF) instead of Normalized Difference Vegetation Index (NDVI) as a remote sensing indicator improved drought detection (based on POD and false alarm ratio, FAR) in central and western parts of India. The framework specified in the drought manual detects most of the major droughts that affected a large part of the country. However, regional droughts in Rajasthan, Gujarat, and Karnataka are frequently missed. Finally, we highlight the limitations in the existing drought monitoring framework and opportunities for its enhancement.