Land Surface Temperature Dynamics in Response to Blue Space Configuration Transformation of Bagri-tract in Lower Gangetic Flood Plain, Eastern India

Abstract: Blue spaces such as wetlands, ponds and rivers contribute significantly to regulating the local thermal environment. This study analyses the dynamics of LST along with the transformation of blue spaces across the Bagri region from 2000 to 2020 with 5 years interval. To detect the change in water bodies, multi-temporal satellite data are used, and also to figure out which indices, such as MNDWI and NDMI, are suitable to detect blue space identification. The results demonstrate that the extent of wetlands has significantly decreased during the study period, from about 30% of wetlands in 2000 to about 12–13% in 2020 (R² ≈ 0.89). In addition, the intensity of the thermal environment has increased, with the maximum LST increasing from about 61.3°C to about 70.4°C. Landscape fraction analysis shows that the values of patch and edge indices have continuously decreased, while the extent of the core area has increased, indicating an integrated change in landscape composition. The multiple linear regression models indicate that landscape composition has a crucial effect on LST. Overall, the results of this study indicate that there is a close relationship between the reduction of blue space and the increase in surface temperature. Therefore, wetland conservation and integrated management of blue space are particularly important for maintaining ecological balance and reducing thermal stress. Keywords: Land Surface Temperature, Blue space configuration, Modified Normalized Difference Water Index, Landscape fragmentation, Bagri tract