2016年12月克拉玛依一次罕见冻雨天气过程分析  

Analysis of a Rare Freezing Rain Weather in Karamay City

作　　者：史昀 史永强 SHI Yun;SHI Yongqiang(Karamay Meteorological Bureau, Karamay 834000, China)

机构地区：[1]克拉玛依市气象局,新疆克拉玛依834000

出　　处：《沙漠与绿洲气象》2019年第2期76-83,共8页Desert and Oasis Meteorology

基　　金：克拉玛依市气象局科研课题(2060499)资助

摘　　要：2016年12月4—5日新疆克拉玛依市出现历史罕见的冻雨天气过程,通过实况观测资料的综合分析,并利用WRF区域模式进行数值模拟,分析冻雨形成的环流形势、风场、大气层结以及冻雨云区的结构特征。结果表明,中亚低槽前的西南锋区上弱短波东移是本次冻雨过程的影响系统,西南急流带为冻雨发生提供充足的水汽条件,逆温层是冻雨发生的必要条件,冻雨在"冰晶层—暖层—冷层"层结下,通过融化机制形成:水汽输送层主要位于冰晶层上,水汽在冰晶层中(特别是-40～-10℃层)凝结为雪花,降落到暖层(0～4℃)充分融化为水滴碰并增长,再进入厚度约1 km的冷层中(低于0℃),迅速冷却为过冷却雨滴或凝固为冰粒。逆温层的强弱是降水物相态变化的关键影响因素,低层暖平流是暖层维持的热力条件,近地面冷平流对于冷层重建也是至关重要的。本次冻雨过程与南方不同的是:克拉玛依降水前期就存在强逆温,并在冻雨发生前逆温层出现减弱后再加强的变化过程。In this paper, the author analyzed circulation situation, wind field, atmospheric stratification and clouds through comprehensive analysis of observation data, and numerical simulation using the WRF regional model for a rare freezing rain weather from December 4 to 5, 2016 in Karamay, Xinjiang. The results showed that the weak short-wave eastward movement in the southwest frontal region was the influence system of the freezing rain process. The southwest jet stream zone provided sufficient water vapor conditions for the freezing rain, the temperature inversion layer was the necessary condition for the freezing rain. Freezing rain was formed by melting mechanism through the stratification of ice crystal layer (especially in the - 40 ℃ to - 10 ℃ layers) to warm layer(0-4 ℃)then to cold layer (<0 ℃).The water vapor transport layer was mainly located on the ice crystal layer, and the water vapor condensed into ice crystals and then fell into the high-humidity warm layer to melt and grow as water droplets, and then fell into the cold layer to cool as supercooled raindrops or ice grains. The strength of the temperature inversion layer was the key factor affecting the phase change of precipitation, the low-level warm advection was the thermal condition for the warm layer to maintain, and the near-surface cold advection was also crucial for the cold layer reconstruction. The most different point between freezing rain in Karamay and the southern China is that there was a strong temperature inversion during the prophase of precipitation, and the temperature inversion layer changed from weakening to strengthening before the freezing rain in the sky of Karamay.

关 键 词：冻雨 层结特征 数值模拟 

分 类 号：P458.121[天文地球—大气科学及气象学]