北京首都国际机场冻雨过程的模拟及其产生的可能机制

Numerical Simulation of a Freezing-Rain Process in Beijing Capital International Airport and the Mechanism for Its Formation

为了探讨北京首都国际机场冻雨过程产生的可能机制,利用NCEP再分析资料、风云2号E星(FY-2E)的云顶亮温(Black Body Temperature,TBB)逐小时资料及风云3号A星(FY-3A)反演的云顶高度日平均资料做为检验依据,使用美国非静力中尺度模式(Weather Research and Forecasting,WRF)对2013年1月31日发生在首都机场附近地区的一次冻雨过程进行模拟,得出以下结论:1)模拟结果中的云顶温度与FY-2E的TBB逐小时资料对应较好:此次冻雨过程,整个降水云系云顶温度在0^-6°C之间,模拟结果水成物的垂直分布也得到了较好的印证;通过FY-3A反演的云顶高度日平均资料的检验,证明此次冻雨过程的云高基本维持在3 km左右,而且云微物理固态项的含量少。2)云顶温度、云顶高度实况与模式模拟表明此次过程是一次典型的暖雨机制冻雨,这说明产生北方冻雨的可能机制并不单一,冰相机制与暖雨机制可以同时存在。

In order to investigate the possible mechanism of freezing rain process, the WRF model(Weather Research and Forecasting) was used to simulate a freezing-rain process occurred on 31 Jan 2013 in the area of the Beijing Capital International Airport. The NECP reanalysis data, the Black Body Temperature(TBB) of FY-2 E, the daily average cloud height data of FY-3 A are used to verify the model simulation. Major conclusions are as follows: 1) The cloud top temperature of the simulation is consistent with TBB of FY-2 E. During the freezing rain process, the cloud top temperature varied between 0--6 °C, and the simulated vertical distribution of the hydrometeors agree well with observations. According to the cloud top height derived from FY-3 A observations, it is found that the cloud top in the freezing-rain process basically remained at around 3 km, and the clouds contained less microphysical solid contents. 2) Observed cloud top temperature and height and the simulation results show that this is a typical warm freezing rain process. This result indicates that the mechanism for the formation of freezing rain in northern China may not be single. Ice-crystal processes and warm-rain processes may simultaneously exist during the formation of freezing rain.