Changing dynamics of urban biophysical composition and its impact on urban heat island intensity and thermal characteristics: the case of Hyderabad City, India
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The biophysical composition; including the green surface cover and moisture dynamics substantially affects the thermal character and Surface Urban Heat Island intensity (SUHII) of an urban area. Therefore, biophysical indices are highly sensitive to the changing process in land use and land cover. Remote sensing based land surface temperature (LST) plays a significant role in analyzing the thermal behavior of urban areas at multiple scales to moderate the urban heat island. In the present study, Greater Hyderabad Municipal Corporation, is taken as a case study to assess biophysical controls on LST and UHI in an urban ecosystem by implementing biophysical indices. Therefore, the cluster of UHI and the proximity to the hotspots were created from spatial statistics. The areal coverage of urban land was increased from 31.2% in 1973 to 62.87% in 2015 with 5.03 sq km year−1 expansion rate. The LST hotspot (H–H) in 2002 observed in the central and the southeast portion of the region, ascribe to the presence of higher thermal anomalies, whereas, the mean LST (°C) of the neighboring region is below than the average. The highest negative correlation between the estimated LST (°C) and the biophysical indices was accounted over aquatic vegetation cover, followed by urban green spaces and built-up urban area, respectively. The simple linear and multiple regression models demonstrated the complex and nonlinear behavior of the UHI and LST with the biophysical components. Therefore, the spatial coherence among the biophysical indices with LST ensembles the necessity of urban greenery and parks within the urban counterpart to mitigate the outdoor thermal discomfort to a reasonable extent.
KeywordsLST SUHI Biophysical indices Thermal comfort Spatial statistics Urban ecosystem
SS acknowledges UGC for providing continuous research fellowship to carry out the research at Indian Institute of Technology (IIT), Kharagpur (India). SB would like to acknowledge INSPIRE Fellowship Programme (Award Number: IF131138) funded by Department of Science and Technology (DST, New Delhi) for doctoral research being carried out at the Indian Institute of Technology (IIT), Kharagpur (India). SR thanks the Ministry of Human Resource Development (MHRD, New Delhi) for providing continuous research fellowship for doctoral work being carried out at the Indian Institute of Technology (IIT), Kharagpur (India). SS and SR appreciates the support and encouragement got from Prof. Somnath Sen, Prof. Saikat Kumar Paul and Prof. Joy Sen, Indian Institute of Technology Kharagpur (India) and, SB are thankful to Prof. M. A. Mamtani, Indian Institute of Technology Kharagpur (India).
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