High-resolution urban heat island analysis using SDGSAT-1 thermal infrared and glimmer data: the case of mainland Shanghai

The Urban Heat Island (UHI) effect is critical for decreasing urban thermal pressure and promoting sustainable development. Nighttime light intensity (NTL), an indicator of human activity and urbanization, plays an important role in influencing UHIs. This study used three-band 30-meter (m) thermal infrared data from SDGSAT-1's Thermal Infrared Spectrometer (TIS) and used the Temperature-Emissivity Separation (TES) algorithm to retrieve surface temperatures of mainland Shanghai. The retrieved land surface temperature (LST) data were cross-validated with Landsat 8/9, producing a root mean square error (RMSE) of 2.06 K. The Surface Urban Heat Island Intensity (SUHII) was then calculated. Using NTL data from SDGSAT-1's Glimmer Imager for Urbanization (GIU), we conducted a spatial autocorrelation analysis of SUHII and its association with NTL, using Global and Local Moran's I. The results showed marked temporal and spatial clustering of SUHII, affected by solar radiation, air temperature, city zoning, and high-energy consumption areas including factories and airports. Bivariate spatial autocorrelation in LISA maps showed high–high (HH) and low–low (LL) clusters, indicating localized correlations between NTL and UHIs. Therefore, with high spatial resolution, SDGSAT-1 achieves accurate identification of urban heat sources, making it a valuable tool for understanding UHI effects and advancing sustainability goals.