新疆阿勒泰地区一次罕见暴雪天气过程分析

2010年1月6—7日阿勒泰地区普降暴雪造成罕见雪灾。通过对常规资料、ECWMF客观分析和T639物理量产品00、03时及06时资料、FY2E红外云图及其黑体亮温分析,对暴雪过程及其成因进行诊断分析。结果表明:500 hPa欧亚范围内呈两槽一脊的Ω型,欧洲和萨彦岭均为深厚低涡、西西伯利亚到泰米尔半岛为强阻塞,及中纬度纬向锋区是造成此次暴雪天气的大尺度系统;地面图上,暴雪产生于中亚气旋前部的暖锋前部及850 hPa中尺度切变线和幅合线附近的重叠区域。高湿区和强上升区,云系的发展和移动均与降雪量有较好的对应关系。单站高空风时间剖面图揭示了暴雪过程中,高低空急流、切变线的变化和暖湿气流的输送;单站的物理量变化对暴雪预报有一定的指示意义。

Analysis of a rare snowstorm process in Altay regions,Xinjiang Uygur autonomous region

A heavy snow results in a rare snow disaster in the Altay region on 6-7 January 2010. Based on the conventional meteorological data, ECMWF products, T639 physical products at 00:00, 03:00 and 06:00 o’clocks, FY2E infrared satellite image and its brightness temperature data, the heavy snow process and its forming reasons were analyzed. The results show that circulation patterns are two troughs and one ridge with shape in the range of 500 hPa over the Asia and Europe. Circulation patterns, deep low vortex over Europe and Sayanling regions, strong blocking from the western Siberia to Taymyr peninsula and front zone in middle latitude are the large scale system for the heavy snow process. According to the surface weather chart, the heavy snow happens near the overlay area of warm front’ foreside of the Central Asian cyclone’ foreside and meso-scale shear line and convergence line in 850 hPa. The development and movement of cloud system are related significantly with snowfall in the high humidity and strong ascending areas. Changes of upper and lower jet as well as shear line and transportation of warm and wet airflow during the heavy snow could be revealed by the wind-time cross-section diagram of high level in single station. Variation of physical quantity in single station is indicative to snowstorm forecast.