Numerical simulations on influence of urban land cover expansion and anthropogenic heat release on urban meteorological environment in Pearl River Delta

Urbanization is an extreme way in which human being changes the land use/land cover of the earth surface, and anthropogenic heat release occurs at the same time. In this paper, the anthropogenic heat release parameterization scheme in the Weather Research and Forecasting model is modified to consider the spatial heterogeneity of the release; and the impacts of land use change and anthropogenic heat release on urban boundary layer structure in the Pearl River Delta, China, are studied with a series of numerical experiments. The results show that the anthropogenic heat release contributes nearly 75 % to the urban heat island intensity in our studied period. The impact of anthropogenic heat release on near-surface specific humidity is very weak, but that on relative humidity is apparent due to the near-surface air temperature change. The near-surface wind speed decreases after the local land use is changed to urban type due to the increased land surface roughness, but the anthropogenic heat release leads to increases of the low-level wind speed and decreases above in the urban boundary layer because the anthropogenic heat release reduces the boundary layer stability and enhances the vertical mixing.