Detection and Analysis of Extreme Temperature Events in Chuadanga, Bangladesh

The Intergovernmental Panel on Climate Change (IPCC) recognizes Bangladesh as highly vulnerable to temperature extremes. According to the Bangladesh Meteorological Department (BMD), heat waves (HWs) occur when temperatures reach 36°C or higher for at least three consecutive days, while cold waves (CWs) are defined by temperatures of 10°C or lower over the same period. The Chuadanga district has experienced the country's most extreme temperatures, for instance, a record high of 43.7°C in April 2024 and a record low of 5.1°C in January 2011. Despite its climatic significance, Chuadanga has received limited attention as a distinct study area. This comprehensive study addresses that gap by integrating hydro-meteorological data (1990–2024), satellite imagery, and public survey findings to examine temperature extremes and their socio-economic impacts. The results show that HWs mainly occur from March to May. Unusual HW occurrences have also been observed in February and September. Elevated humidity in September contributes to a higher heat index (44.6°C in 2023) compared to April (40.7°C in 2022). In contrast, CWs occur mostly in December-February with the highest frequency, 43 events in 2010. However, the number of CWs dropped significantly (e.g., 42 CWs in 2019, whereas there were 16 CWs in 2024). Remote sensing analysis shows that approximately over 50% of HW days coincide with positive daytime MODIS Terra land surface temperature anomalies. Decadal land-use and land-cover assessments suggest minor changes in water bodies, vegetation, and open land. However, a 35-year record shows a continuous decline in the Mathabhanga River water levels, reducing regional evaporative cooling potential and contributing to temperature extremes. These findings suggest that regional climate change and large-scale atmospheric processes, rather than local land-cover changes, are the main drivers of extreme heat. Survey results (conducted among Chuadanga's low-income residents) further reveal that nearly 80% of respondents experience severe impacts on work efficiency and health during HWs, highlighting the urgent need for targeted adaptation and mitigation measures.