Spatio-temporal characteristics of meteorological and agricultural drought indices and their dynamic relationships during the pre-monsoon season in drought-prone region of Bangladesh

Abstract

The global water crisis has become a rising concern against the background of climate change, which is responsible for increasing drought frequency, a devastating natural hazard that severely affects the agricultural sector of a nation. Due to the geographical position, spatial variation in seasonal precipitation patterns, and groundwater table, the northwestern part of Bangladesh is one of the most drought-prone regions with extensive irrigation practices. In recent decades, the frequency of meteorological drought has significantly increased, but its dynamic relationship with agricultural drought is still unclear. In this research, we aim to study the meteorological and agricultural drought conditions and their dynamic relationships during the pre-monsoon season (March-May) in northwest Bangladesh. For this, we analyzed the 3-month standardized precipitation index (SPI), Palmer drought severity index (PDSI), and 3-month standardized precipitation evapotranspiration index (SPEI) to study the meteorological drought, and the normalized difference vegetation index (NDVI), land surface temperature (LST), vegetation condition index (VCI), temperature condition index (TCI), and vegetation health index (VHI) using MODIS to study the agricultural drought. Results revealed that SPI-3 and SPEI-3 during the pre-monsoon increased, while PDSI decreased. Agricultural drought indices showed a better VHI status in 2021. The Pearson correlation among these indices represented no correlation between meteorological and agricultural drought. This research identified that the relationship between VHI and SPI-3 might not be positive in all cases, especially in extensively irrigated regions. Therefore, it is important to consider hydrological drought indices to improve the understanding and accuracy of drought assessment.