摘要
本文通过耦合AFWA(Air Force Weather Agency)冻雨参数化方案的WRF模式,对2020年冬季因暖锋引发的中国北方严重冻雨灾害个例进行了模拟,结果显示模式能够很好地模拟此次冻雨过程中降水相态的空间分布。通过分析暖锋的演变、水成物云微物理特征以及降水相态的变化,得到:在辽宁中北部—吉林中东部地区,暖锋导致中低空形成“冷—暖—冷”的温度层结,该区冻雨形成机制以“冰相机制”为主,即高空的雪花落入大于0℃暖层内融化、再降落到次冻结层后形成冻雨。同时,发现存在高空无固态水成物、逆温层内暖雨下落到次冻结层在地面形成冻雨的现象,这种新机制被定义为“暖雨机制”,更多水成物垂直剖面与同期地面观测降水相态的比对,验证了新机制的存在,并解释了该机制形成的可能原因。为更深入理解冻雨形成机理以及北方冻雨的预报、预警提供科学支撑。
A warm front-induced severe freezing rain event in northern China in 2020 was simulated by using the Weather Research and Forecasting(WRF)model coupled with the Air Force Weather Agency(AFWA)freezing rain parameterization scheme,which indicates that the model can well simulate the spatial distribution of the precipitation phase during this freezing rain event.Results from the analyses of the warm front evolution,microphysical characteristics of hydrometeors in clouds,and changes in the precipitation phase show that in the central northern part of Liaoning and the central eastern part of Jilin,a warm front causes the formation of a“cold-warm-cold”temperature stratification in the middle and low altitudes.The formation mechanism of freezing rain in this area is mainly based on the“ice phase mechanism”,which means that high-altitude snowflakes fall into the warm layer above 0℃and melt,then fall into the sub-freezing layer to form freezing rain.At the same time,the phenomenon of the absence of solid-state water particles in the higher altitudes,warm rain falling within the temperature inversion layer to the sub-freezing layer and forming freezing rain on the ground was observed,which is firstly defined as the“warm rain mechanism”,and further comparisons between vertical profiles of hydrometeors and concurrent ground-based observations of precipitation phase confirm the existence of this new mechanism,and the potential reasons for its formation have been explained.The validation of the“warm rain mechanism”sheds light on the mechanisms underlying freezing rain formation and provides scientific basis for improving the forecasting and warning systems for freezing rain events in northern China.
作者
曾箐芃
韩永翔
陆正奇
李嘉欣
刘唯佳
ZENG Qingpeng;HAN Yongxiang;LU Zhengqi;LI Jiaxin;LIU Weijia(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044,China;Zhejiang Institute of Meteorological Sciences,Hangzhou 310008,China;Hangzhou Meteorological Bureau,Hangzhou 310051,China)
出处
《气象科学》
2024年第1期147-156,共10页
Journal of the Meteorological Sciences
基金
国家自然科学基金面上资助项目(42075063,42275077,42230604)。
关键词
云微物理过程
北方冻雨
冻雨形成机制
WRF模式
cloud microphysics
northern freezing rain
formation mechanism of freezing rain
WRF model
