Assessment of meteorological and agricultural droughts using remote sensing and their impact on groundwater in an agriculturally productive part of Northwest India.

Wheat is an important component of global food security, and Punjab and Haryana are the major wheat-growing areas in Northwest India, but climate change has increased the frequency of droughts in this region. Timely, precise, and effective drought monitoring is critical to ensure food security. In the present study, meteorological and agricultural droughts were assessed using standard precipitation index (SPI) and remote sensing-based indices, namely vegetation health index (VHI) and normalized vegetation supply water index (NVSWI) during the Rabi season (wheat growing season) in three different agroclimatic zones (ACZs i.e., ACZ I: Hot arid agro-climatic zone, ACZ II: Semi-arid agro-climatic zone, and ACZ III: Hot sub-humid agro-climatic zone) of Punjab and Haryana. Furthermore, correlations between NVSWI, VHI, SPI, and gross primary productivity (GPP) were investigated, as well as trend analysis of NVSWI and groundwater level to better understand their interrelationships and the impact of agricultural droughts on groundwater level. The results of SPI indicated that ACZ III witnessed more drought episodes than ACZ I and II. The driest years in ACZ I, ACZ II, and ACZ III were 2002–03, 2014–15, and 2016–17, respectively, while the year 2018–19 was observed as normal in all the ACZs. A significant high correlation was observed between the NVSWI and VHI and the NVSWI and GPP in all three ACZs, while SPI did not exhibit a significant correlation with the NVSWI in ACZ II and III. The Mann-Kendall Test and Sen's slope indicated a declining groundwater trend in all the ACZs and an increasing trend in NVSWI values. The results underline the robustness of SPI and NVSWI in drought monitoring in semi-arid and arid zones of northwest India. Rainfall variability and increased groundwater use for irrigation practices in semi-arid and hot sub-humid areas are leading to groundwater decline. [Display omitted] • Meteorological droughts, their severity and intensity were assessed using SPI. • Normalized Vegetation Water Supply Index (NVSWI) was used for agricultural droughts. • Relationships between meteorological and agricultural droughts were studied. • NVSWI can efficiently monitor the agricultural drought events in Punjab and Haryana. • Declining trend in groundwater level was observed due to irrigational practices. [ABSTRACT FROM AUTHOR]