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Analysis of urban heat island and urban ecological quality based on remote sensing imagery transformation in semarang city

Urban physical and biotic heterogeneity phenomena that caused by the decrease of vegetation and the expansion of built-up land can influence the urban climate response. The increase of land surface temperature brings on the Urban Heat Island (UHI) phenomenon. Spectral resolution, temporal resolution, and the synoptic overview capability of remote sensing data are capable in urban study. Remote sensing imagery is able to extract the land surface temperature changes widely and simultaneously. The aims of this research are to identify UHI phenomenon and analyze the ecological condition in Semarang City using Landsat 7 ETM+ in 2002 and Landsat 8 OLI in 2019. Urban Thermal Field Variance Index (UTFVI) transformation is used to measure the intensity of UHI. Remote Sensing Ecological Index (RSEI) that based on principal component analysis transformation is used to analyze the urban ecological quality with the occurrence of UHI phenomenon. The results show that the land surface temperature mean value increase to 3,19°C so that some parts of Semarang occured UHI. The trend is also increased and stronger. It is consistent with the decrease of RSEI. The increase of temperature and UHI phenomenon during 2002-2019 impact on the degradation of urban ecological quality in Semarang City.