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

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.

为探讨人为热(AH)对华南暖区暴雨的影响,该文利用WRF-SLUCM模式并考虑适当的AH释放,对2014年5月8日发生在珠江三角洲(PRD)的暖区暴雨进行了数值模拟。有无AH效应的模拟结果分析表明,降水对AH的影响敏感,AH效应使得城区总降水量减少约10%。影响的可能机制为:AH增加导致的热力场和流场再分布,使得局地辐合向PRD边界区域转移增强城乡边界的对流和降水;PRD城区内更为均质的城市热环境减小了热力对比削弱了辐合,从而降低了城区降水。