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

Abstract

Mapping high-resolution Anthropogenic Heat Flux (AHF) is crucial to climate simulations and surface energy balance studies in urban areas. Nighttime Light (NTL) data is a 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 multi-source data fusion was proposed in this study. Then, 100-m grid AHF based on the downscaled NTL data in the Beijing-Tianjin-Hebei region was mapped and evaluated quantitatively. The results show that: 1) The downscaled NTL data 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 micro-scale urban studies as a supplement to the Luojia1-01 NTL; 2) Among various AHF estimation models, the power function model based on the VIIRS-HD has the highest fitting accuracy, with R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 0.87 and RMSE of 0.57 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ; 3) Comparison of multiple scales with existing products shows that the 100-m AHF mapping in this study has better spatial performance, and the distribution is more reasonable. 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.