利用WRF-Chem模式模拟分析人为气溶胶对台风Fitow(1323)强度及降水的影响

利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5) 对1323号台风Fitow进行了模拟，设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验，对比分析了人为气溶胶对台风的影响。结果表明:人为气溶胶对台风移动路径影响较小。人为气溶胶增加，台风强度减弱，台风主体总累积降水量减少，靠近陆地阶段台风主体降水率减少。气溶胶的增多可提供更多的凝结核，台风外围云水增加，更多的云水可上升至冻结层以上形成过冷水，促进冰相粒子的形成，释放的潜热增加，使外围对流增强，降水增加。台风外围对流的发展，使低层入流的暖湿空气更多的在外围上升，向台风中心的入流减弱，眼墙的发展减弱，降水减少，台风强度减弱。台风外围的对流发展弱于眼墙的对流，降水仍以眼墙区为主，使累积降水量和降水率整体上表现为减少。

Simulations of Anthropogenic Aerosols Effects on the Intensity and Precipitation of Typhoon Fitow (1323) Using WRF-Chem Model

To investigate the impacts of anthropogenic aerosols on typhoon Fitow, the No. 23 typhoon in 2013, three simulations with zero, normal and increased anthropogenic emissions were conducted by using WRF-Chem V3.5 (Weather Research and Forecasting Model coupled to Chemistry Version 3.5). Comparison of the results shows that anthropogenic aerosols could hardly influence the track of Fitow. The increased anthropogenic aerosols led to weakened intensity, reduced total accumulated precipitation and decreased precipitation rate in typhoon main body during the phase when Fitow approached the land. Increased aerosols could provide more cloud condensation nuclei, which leads to increased cloud water at the periphery. Therefore, more cloud water could rise above the freezing level and produced more supercooled water, which provided an advantage for the forming of ice particles. These processes not only released extra amount of latent heat, but also enhanced the convection and precipitation at the periphery of typhoon. Furthermore, the invigorated convection at periphery caused an increase in warm and moist air lifted there and a decrease in inflow reaching the typhoon center, and hence resulted in a weakened eyewall and precipitation near the eyewall. The strength of typhoon was weakened. Precipitation at eyewall still dominated precipitation over the typhoon main body due to the weaker convection at its periphery. As a result, total accumulated precipitation and precipitation rate in the typhoon main body both decreased.