Contribution of Urban Surface Expansion to Regional Warming in Beijing, China

Abstract

he contribution of urban surface expansion to regional warming based on meteorological observational station data may vary with significant uncertainty because of its spatial heterogeneity, which promotes a requirement for numerical model-based investigations. Satellite-based images from 1980 to 2016 with fine-resolution over three city clusters and displaying the urban surface expansion in China due to rapid economic development and anthropogenic activity were used to perform 37-year nested dynamical downscaling using the Weather Research and Forecasting model (WRF). The urban surface areas in Beijing expressed marked expansion in the last 37 years. The contribution of urban surface expansion to regional warming was approximately 22% of the overall warming in Beijing and was stronger in the plains areas of Beijing (42%). The contributions to land-use grids that changed from non-urban (in 1980) to urban (in 2016) (N2U) were much stronger than those to grids that were classified as urban in both time periods (U2U), which were closer to the values of urban areas (including N2U and U2U) because of the intense increase in urban surface areas. Urban-related warming expressed marked annual variation and was greater in the warm seasons and smaller in the cold seasons. The greater increase in surface air temperature (SAT) minimum and the weaker SAT maximum accounted for the decreased diurnal temperature range.