A study of meteorological drought via the SPI and SPEI with special reference to groundwater depth in the drought prone area of West Bengal

Drought is a worldwide phenomenon that affects almost all geographical regions, causing enormous harm to both the natural environment and human life. Drought frequency and intensity vary according to natural and anthropogenic factors. It has a significant impact on agriculture, hydrology, economics, ecology and human societies. Recognizing the implications for drought preparation, mitigation, and action. Moreover, identifying and mitigating drought vulnerability is essential for decision makers. Meteorological drought analysis provides a thorough examination of all meteorological factors, such as precipitation, wind speed, relative humidity, dew point, vapor pressure and evaporation. The standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) at different timescales were used for 1998--2018 to analyze the drought characteristics. According to SPI calculations, the months of January through July are experiencing extreme drought. According to the SPEI, the extremely dry months are from March to August and from October to December. The results of the Mann‒Kendall (M-K) test and Sen's slope analysis revealed that the postmonsoon drought tendency increased more rapidly than did the other two periods. Holt-Winter’s test calculates the trend with seasonal change. It was used to anticipate the weather for the following 10 years and indicated that the drought propensity would worsen in the next years. The groundwater level is an essential indicator of water availability for humans. In the tropics, groundwater levels respond to excessive precipitation. As drought can be observed during the postmonsoon season, the postmonsoonal water level depth tends to rise gradually.