Assessment of heatwave, drought, vegetation and moisture content using remote sensing and GIS: a comprehensive study in North-Western part of Bangladesh

This study examines the interplay of heatwaves, droughts, vegetation health, and moisture content in the northwestern region of Bangladesh using remote sensing and GIS techniques. Climate indices, including the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Temperature Condition Index (TCI), and Land Surface Temperature (LST), were analyzed alongside vegetation and moisture indicators, such as the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI). Pearson correlation analysis revealed a strong negative correlation between LST and NDVI (- 0.995), indicating that rising temperatures significantly reduce vegetation density. NDVI values ranged from - 0.14 to 0.58, reflecting sparse vegetation in drought-prone areas. Also, a positive correlation of 0.956 between LST and NDWI indicates that higher surface temperatures are strongly associated with reduced moisture levels or drier conditions in these areas. That means when LST rises, the NDWI values consistently and significantly decrease, reflecting a drop in environmental moisture. NDWI values, predominantly negative throughout the period, indicated a persistent decline in moisture availability. The analysis of drought indices highlighted SPEI's superior performance in capturing drought severity, with Rajshahi and Pabna witnessing the most significant increases in drought occurrences. Over the study period (2013-2022), TCI values consistently identified moderate to extreme drought conditions, with LST reaching as high as 52.12 degrees C in extreme drought-affected areas. These findings emphasize the urgent need for adaptive strategies to mitigate the escalating effects of climate change on agricultural productivity and ecological stability in this vulnerable region. Previous studies in Bangladesh have focused on small regions using limited indicators. However, no comprehensive research has combined multiple drought and heatwave indices such as SPI, SPEI, TCI, LST, NDVI, and NDWI over a large-scale area in the northwestern part of Bangladesh. This study addresses this gap by integrating multiple indices to assess environmental dynamics from 2013 to 2022.