Urbanization and rainfall variability in the Beijing metropolitan region

In this study, rainfall variability in the Beijing metropolitan region and its link to urbanization during the first 10 years of the twenty-first century (2000-09) was examined. Analyses are based on both observations and regional climate model simulations. The study was focused on August, one of the summer months that receive most of the warm season precipitation in Beijing. Observations from surface stations and weather radars in Beijing and its surrounding regions along with satellite observations from the Tropical Rainfall Measuring Mission (TRMM) are used to characterize the spatial and temporal variability of precipitation. It is found that the urban area has fewer rain days and higher rainfall intensity compared to its surrounding region. This suggests a possible impact of urbanization on the spatial variability of rainfall for the region. Regional climate model simulations with the Weather Research and Forecasting (WRF) Model are thus performed with two land use-land cover datasets that represent different stages of urbanization in the Beijing metropolitan region to investigate such an impact. The modeling study demonstrates how urbanization modifies the surface energy budget and the planetary boundary layer, which in turn affects the production of precipitation.