2014年呼伦贝尔市一次中到大雪天气成因分析

Analysis on the Cause of a Moderate to Heavy Snow Weather at Hulunbeier Area in 2014

文章利用常规气象观测资料和NCEP2.5°×2.5°的每6h分析资料,对2014年2月26日发生在呼伦贝尔市中到大雪天气过程进行了动力学分析,结果表明:⑴本次降雪过程是产生在欧亚大陆中高纬度两脊一槽型的环流形势下,500h Pa上低槽是主要的影响天气系统。亚洲中纬度为纬向锋区,并有低槽活动。⑵地面高压从西伯利亚移入贝加尔湖以西到蒙古中西部,蒙古东部、贝加尔湖有气旋。⑶上升气流与高空急流汇合产生强上升运动,高层强辐散的抽吸作用对本次中到大雪的形成起了重要的作用。⑷西南低空急流的形成对水汽源源不断向我市输送起重要作用。

Based on the observation data and NCEP（2.5°×2.5°）6h reanalysis data, the synoptic dynamic analysis of the heavy snowfall process in Hulun Buir region in 26Febrary2014 was made.The result shows that several factors have play important roles in the heavy snowfall process as follows： ⑴ The snowfall was generated in the circulation pattern of two ridges and a groove in the mid-high latitudes of Eurasia, low trough is a major weather systems in 500 h Pa.There was a zonal frontal zone at mid-latitude in Asia, and had low trough acted. ⑵ High pressure in Siberia shifted from west of Lake Baikal to western Mongolia, there was a cyclone in eastern Mongolia、Lake Baikal. ⑶ The convergence of updraft and high-altitude jet stream produced strong upward motion, senior strong suction effect of the divergence played an important role in the formation of this snow. ⑷ The formed of a southwest low-level jet stream played an important role in steadily transporting water vapor to the city.