Characterizing Urban Growth and Land Surface Temperature in the Western Himalayan Cities of India using Remote Sensing and Spatial Metrics

Abstract

Urban heat island (UHI) is developing in major cities of India due to increased urbanization and decreased vegetation cover. Urbanization induces substantial land use changes resulting in surface transformation and thermal emissions which modifies urban microclimate posing serious risk to human health, environment and ecology of the Himalayan ecosystems. Therefore, an improved understanding is required to mitigate UHI. The study illustrates the impact of urbanization on land surface temperature (LST) in the capital city- Shimla and Dehradun in the western Himalayan, India using satellite datasets. The process has been analyzed using urban cover patterns derived from Landsat 5, 7 and 8 with respective sensors of TM, ETM+, and OLI. Built-up and non-built-up areas were extracted and biophysical parameters NDVI, NDBI, NDWI and LST were computed to capture different characteristics of urban growth. The result indicated that during study period, built-up areas have increased from 32.19 Km2 (2000) to 68.37 Km2 (2016) for Dehradun and 12.38 Km2 (2000) to 29.47 Km2 (2016) for Shimla which has manifested an increase in NDBI and LST and decrease in NDVI and NDWI. The results revealed that temperature hotspots were maximum in built-up areas followed by vegetation and water body. We observed significant correlation (p < 0.05) between LST and biophysical parameters -NDVI, NDBI, NDWI. Spatial metrics at class and landscape-level has indicated that landscape has fragmented, became more heterogeneous from 2000 to 2016 because of increased urban growth. The trends identified for changes in landscape patterns and their ramifications in respective areas have prospective policy implications.