Sensitivity of warm-sector heavy precipitation to the impact of anthropogenic heating in South China

Abstract

Previous studies have mostly focused on the effect of anthropogenic heating (AH) on air pollution events. However, few studies have investigated the impact of AH on the warm-sector precipitation over South China. By using the Weather Research and Forecasting model (WRF) coupled with an urban canopy model with appropriate AH release values, the warm-sector heavy rainfall event that occurred over the Pearl River Delta (PRD) during 8 May 2014 was investigated. The results show that the warm-sector precipitation of the PRD is sensitive to the impact of AH. By affecting the convection in the initiation of precipitation, AH can reduce the total precipitation of urban areas by approximately 10%. The possible mechanism by which AH influences the warm-sector heavy precipitation is described as follows: AH induced local convergence shifts towards the border of the PRD and intensified the convection and precipitation therein, by rearranging the thermal distributions of the flow field. In addition, AH changed the local convergence within the urban PRD areas, which was weakened by the homogenous urban thermal environment, and thereby decreased the total urban precipitation.

Keywords

• Heavy precipitation
• anthropogenic heating
• numerical simulation