Spatial Distribution and Seasonal Changes of Urban and Suburban Surface Radiation Budget in Beijing

Under the context of rapid urbanization, radiation budget is crucial to analyse the adverse climate effects in urban environments, especially for mega-cities. Selected Beijing city and surrounding regions as the study area, this paper investigated the spatial distribution patterns and temporal variations of radiation budget based on integration of remote sensing images and ancillary data. Landsat-5 Thematic Mapper (TM) images and meteorological data acquired in the summer and winter were used to calculate land surface parameters and the net radiation flux. Validation with in situ measurement shows that the calculation of net radiation yielded high accuracy. In order to understand the spatial patterns of radiation budgets, the net radiation flux, albedo, and land surface temperature were analysed in terms of variations among different land cover types. Results indicate that the city can be characterized as a “basin” of net radiation in the summer, while a “plateau” in the winter. The albedo and land surface temperature were two primary factors contributing to the spatial variations of net radiation, while the solar elevation angle controlled the seasonal variations of the absolute amount. * Corresponding author.