Mapping Regional High-Resolution Anthropogenic Heat Flux With Downscaled Nighttime Light Data

Mapping high-resolution anthropogenic heat flux (AHF) is crucial to climate simulations and surface energy balance studies in urban areas. Nighttime light (NTL) data are commonly used spatial proxy in AHF estimation. However, the lack of high-resolution NTL data greatly limits the regional high-resolution AHF estimation. To address this problem, a high-resolution (i.e., 100 m) AHF estimation scheme by downscaling the Suomi National Polar-orbiting Partnership (Suomi-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) NTL data with the spatial resolution of 500 m based on multisource data fusion was proposed in this study. Then, a 100-m grid AHF based on the downscaled NTL data in the Beijing–Tianjin–Hebei region was mapped and evaluated quantitatively. The results show the following. First, the downscaled NTL data VIIRS-high definition (VIIRS-HD) has better expressions in structural features of the road network and the spatial distribution of human activity intensity. Meanwhile, it has good consistency with Luojia1-01 NTL in transect and spatial distribution. This indicates that the downscaled NTL is potentially applicable to microscale urban studies as a supplement to the Luojia1-01 NTL. Second, among various AHF estimation models, the power function model based on the VIIRS-HD has the highest fitting accuracy, with $R^{2}$ of 0.87 and RMSE of 0.57 W/m2. Third, a comparison of multiple scales with existing products shows that the 100-m AHF mapping in this study has better spatial performance and more reasonable distribution. This study proposed a new estimation scheme for the regional high-resolution AHF mapping, which will better serve urban climate simulation and surface energy balance studies.