大兴安岭地区的一次暴雪天气诊断分析  

Diagnostic Analysis of a Snowstorm in Daxinganling Region

作　　者：张桂莲 姚晓娟 孙永刚 孟雪峰 仲夏 刘文炜 Zhang Guilian;Yao Xiaojuan;Sun Yonggang;Meng Xuefeng;Zhong Xia;Liu Wenwei(Inner Mongolia Autonomous Region Meteorological Observatory,Huhhot 010051;Wuhai Meteorological Service,Inner Mongolia,Wuhai 016000)

机构地区：[1]内蒙古自治区气象台,呼和浩特010051 [2]内蒙古乌海市气象局,乌海016000

出　　处：《气象科技》2018年第5期971-978,共8页Meteorological Science and Technology

基　　金：内蒙古自治区气象局预报员暴雪创新团队项目;内蒙古自治区气象局青年基金研究项目(nmqnqx201812)资助

摘　　要：利用常规观测资料、FY-2气象卫星水汽云图、多普勒雷达资料、NCEP(1°×1°)逐6h再分析资料对2016年11月13—14日东北冷涡背景下的大兴安岭地区暴雪天气过程进行分析。结果表明:高空冷涡后部横槽南摆,使干冷空气南下以及冷涡前部西南低空急流北上且辐合急剧加强为暴雪天气提供了非常有利的环流背景;≥20m·s-1的西南低空急流作为水汽输送带,为暴雪区提供了充足的水汽来源;垂直上升运动中心和散度辐合辐散中心基本耦合且加强,为暴雪提供了强有利的动力抬升条件,有利于上升运动的增强发展;暴雪是发生在条件对称不稳定的(湿位涡MPV2<0)的背景下,暴雪中心位于MPV2等值线密集带以及MPV2绝对值得到较大增长的区域。水汽图像上有表征干侵入特征的干缝、斧形暗区等;雷达回波显示低层东南风急流非常显著,低层强烈发展的东南暖湿气流与东北—西南走向的大兴安岭山脉相垂直时,地形强迫抬升不仅使迎风坡的垂直上升运动迅速加强,而且使低层水汽辐合得到加强和维持为暴雪提供了充足的水汽,这也是暴雪主要集中在大兴安岭东麓的重要因素。The snowstorm process against the background of northeast cold vortex in the Daxinganling region on 13 and 14 November 2016 is analyzed using the routine observational data,FY-2 satellite water vapor images,Doppler radar data and NCEP（1°×1°）reanalysis data with the resolution of 6 hours.The results indicate that the transversal trough from the rear of the upper cold vortex southward caused the dry-cold air southward and the low-level southwest jet in front of the cold vortex northward-jumping;moreover,the convergence which strengthened sharply provided the favorable circulation conditions for the snowstorm.The low-level southwest jet（≥20 m·s-1）as the moisture transport belt provided adequate water vapor for the snowstorm.The center of the vertical ascending motion was corresponding to the location of the center of the convergence and strengthened gradually,which offered the dynamic conditions for the snowstorm and promoted the development of ascending motion.The snowstorm process occurred against the background of the conditional symmetric instability where the moist potential vorticity MPV20 occurred,and the center of snowstorm was located in the intensive belt of MPV2 isolines and the area where MPV2 absolute value increased greatly.The water vapor image shows the dry seam and hatchet dark areas which is the characteristics of the dry intrusion.The radar echo shows that the low-level southeast jet was very significant.When the ultrastrong lower level southeast warm and moist air was vertical to the Daxinganling Mountains from the northeast to southwest,due to the topography effect,the ascending motion on the windward slope strengthened rapidly and the moisture convergence in lower layers strengthened and maintained,which offered the abundant moistures for the snowstorm,which was a major reason why the snowstorm was mainly distributed in the eastern foot of Daxinganling Mountains.

关 键 词：暴雪 低空急流 干侵入 湿位涡 水汽图像 

分 类 号：P458[天文地球—大气科学及气象学]