Geospatial mapping of heatwaves and drought: Exploring their link to vegetation, soil moisture, and groundwater in the thirsty Barind Tract, Bangladesh

This research examines the spatiotemporal scrutiny of droughts and heatwaves in the high Barind Tract of Northwestern Bangladesh and how they relate to vegetation, soil moisture, and groundwater levels. The research employs a novel methodology, combining the meteorological-based Standardized Precipitation Index (SPI) and remotely sensed land surface temperature (LST) to compute heatwave metrics and droughts. The connection between extreme occurrences with vegetation and soil moisture is examined using the normalized difference vegetation index (NDVI) and the normalized difference moisture index (NDMI). The findings show that the frequency, period, and severity of heatwaves in the area have significantly increased. The SPI values and Groundwater table (GWT) depth have a robust association, with increasing SPI values corresponding to GWT regaining and vice versa. Sometimes, even with positive SPI values, the GWT depth constantly rises. Changes in cropping patterns and overuse of groundwater are to blame for this. Drought threatens the groundwater-based agricultural practices used in the Barind area. The research confirms that arid or semi-arid regions are hydrologically vulnerable to extreme events and highlights the need for future mitigation and adaptation plans.