Spatiotemporal assessment of land use and land cover and associated impact on land surface temperature in a low-lying deltaic region, India
摘要
Kuttanad, in Alappuzha district of Kerala, India, is a delta formed by four major rivers: Pampa, Achankovil, Meenachil and Manimala. This study investigates Land Use and Land Cover (LULC) changes over four decades under the level 1 classification of the United States Geological Survey (USGS). Landsat 5 TM, Landsat 7 ETM+ and Landsat 8 OLI data from 1988 to 2023 were analyzed using the Maximum Likelihood Classification (MLC) algorithm. Five satellite images were considered to assess the spatial expansion of built-up areas. Landsat 8 OLI data from 2014 and 2021 were used to examine the associated Land Surface Temperature (LST) patterns. LULC was categorized into agricultural land, waterbodies, wetland and built-up land. Wetlands declined by 62.75% from 1988 to 2023, while built-up land increased significantly, doubling each decade. LST increased by 4.72°C from 2014 to 2021, with Coefficient of Variation values of 25.12 and 31.31, respectively. LST was higher in wetland and built-up areas. The correlation between LST and Normalized Difference Built-up Index (NDBI) was 0.84 in 2014 and 0.73 in 2021. Classification accuracy ranged from 89.60 to 91.20% (Kappa: 0.85–0.87). The results provide a novel baseline that links LULC and LST trends to rising flood risk and sustainable land-use planning.
Research highlightsBuilt-up land in the study region increased significantly from 74.42 to 420.62 km2 between 1988 and 2023, marking a rise of 465.19%. A total of 202.87 km2 of wetland has been converted to built-up land during this period. The area of waterbodies has decreased by 18.04% from 1988 to 2023. A rise of 4.72°C in Land Surface Temperature (LST) was observed in Kuttanad between 2014 and 2021. The increase in LST is attributed to the expansion of built-up areas.