Observational and modeling study of urban effect on weather variables in Guangzhou-Shenzhen, South China

Abstract

Statistical Analysis on climate change in South China has revealed great urban effect in the cities of Guangzhou and Shenzhen. The urban effect was found to have influence on daily minimum temperature (Tmin) increase, daily mean temperature (Tmean) increase, precipitation increase, as well as daily relative humidity decrease in these two cities. In this study, the Weather Research and Forecasting (WRF) model coupled with Noah land surface model and a single-layer urban canopy model (UCM) (WRF-LSM-UCM) is used to simulate these urban weather features in Guangzhou and Shenzhen. We use the land use data of Guangzhou and Shenzhen in 1980 and 2000 respectively to simulate the different land-use effect scenarios. From the model simulation, it was found that the effect of land-use change on temperature is not significant, but the anthropogenic heat (from urban area) corresponding to the change of land-use contributes a great impact on local temperature change. WRF-LSM-UCM can simulate urban effect well in Guangzhou and Shenzhen region. Urban effect tends to increase temperature more in Winter than in Summer and increase Tmin more than Tmax, which leads the decrease of diurnal temperature range (DTR). Furthermore, the simulation of urban effect on precipitation and relative humidity in the study region by WRF-LSM-UCM will be presented.