2015年12月乌鲁木齐极端暴雪成因分析  

Analysis of Extreme Blizzard in December 2015 in Urumqi

作　　者：许婷婷 张云惠 于碧馨 郑育琳 

机构地区：[1]新疆气象台,新疆乌鲁木齐830002

出　　处：《沙漠与绿洲气象》2017年第5期23-29,共7页Desert and Oasis Meteorology

基　　金：国家自然科学基金项目(41565003);科技部公益性行业(气象)科研专项(GYHY201506009)共同资助

摘　　要：利用常规观测资料、NCEP FNL(1°×1°)再分析资料以及卫星、雷达回波资料,对乌鲁木齐2015年12月10—12日的极端暴雪天气过程的环流演变及暴雪产生和维持的机制进行了初步分析。结果表明:此次暴雪过程是欧洲脊发展推动乌拉尔山地区长波槽东移南压,同时配合低层风场的辐合切变、地面冷锋及地形强迫抬升等共同作用造成的。500 h Pa偏南气流,700h Pa、850 h Pa的偏北气流在乌鲁木齐的交汇有利于加强冷暖空气的汇合和水汽的聚集,为乌鲁木齐强降雪提供有利的动力条件。各物理量场的配合及地形作用使得大暴雪持续时间长,降雪强度大;降雪前期乌鲁木齐逆温使不稳定能量集中释放;散度辐合中心最强时段及上升运动均与降雪时段对应,乌鲁木齐地形引起的强迫抬升为暴雪提供有利的垂直环流;水汽的主要来源为阿拉伯海及孟加拉湾,且水汽在中低层的辐合上升明显,水汽通量散度辐合中心的出现时间对大暴雪的最强降水时段有很好的指示意义。Using conventional observation data, NCEP /FNL （1°×1°） reanalysis data, in combinationwith radar and satellite data in Urumqi, the circulation evolution and the mechanism of thegeneration and maintenance of an extreme blizzard process occurred in Urumqi during 10th-12thDecember, 2015 are preliminary analyzed. The results show that the cause of the blizzard process isthe development of European ridge which promotes the long wave trough of Ural Mountains eastwardand southward and the cooperation with convergence and shear of low-level wind, ground cold frontand topographic forcing uplift etc. The coordination of various physical fields and the role oftopography make the Urumqi heavy snow the convergence of the south airflow on 500 hPa and thenorth airflow on 700 hPa and 850 hPa in Urumqi can strengthen the confluence of cold and warmair and the gather of water vapor, besides, it also can provide favorable dynamic conditions for theblizzard in Urumqi. The temperature inversion over Urumqi makes the unstable energy releaseconcentrically in the early stage of snowfall. The period of the convergence center of divergence andascending motion are corresponding with the period of snowfall. Forced uplift of Urumqi landformprovides favorable vertical structure for blizzard. The main source of water vapor of this blizzard isthe Arabian Sea and the Bay of Bengal, and converging ascending motion of water vapor at lowlevels increase significantly, the appearance of the convergence center of moisture flux divergencehas a good indication of this strongest precipitation period of Urumqi Blizzard.

关 键 词：极端暴雪 高低空配置 物理机制 中尺度 

分 类 号：P458.122[天文地球—大气科学及气象学]