摘要
利用常规气象观测资料和NCEP/NCAR逐日6 h再分析资料,对2010年1月4～7日新疆北部持续暴雪过程的环流特征及物理量场进行诊断分析。结果表明:北半球中高纬阻塞高压维持时间长、切断低压稳定提供了降雪"持续性"的环流背景。切断低压不断分裂短波并西退再东移是造成降雪的影响系统;降雪区大到暴量的强降雪时段,850 hPa上维持10～16 m/s的西北风与8～10 m/s东南风的强辐合线,700 hPa上为风速辐合区,500～200hPa逐渐转为风速的辐散区。形成对流层低层强辐合、中高层强辐散及整层强的上升运动;水汽输送主要为西南路径,也有一定量西北方的水汽来源。在55°N附近有一支自东向西再自北和西北向南再向东南的水汽输送带,这支水汽输送带上最大的水汽通量占西南方向水汽量的近1/4,多方水汽的输送是新疆北部出现历史罕见强暴雪的主要原因。
In this paper,the circulation features and physical scalar fields of a continuous snowstorm over north Xinjiang,China during the period from January 4th to 7th,2010 are analyzed based on the observed meteorological data and the daily 6-hour reanalyzed data of NCEP/NCAR.The results reveal that the long duration of blocking high and the stable cutoff low over the mid-high latitudes of the Northern Hemisphere provided a circulation background for the snowstorm.The cutoff low generated continuously short waves,moved back westward and then eastward,and affected the snowstorm;over the snowy area during the heavy snowy period,the strong convergence lines of northwest wind（10-16 m/s） and southeast wind（8-10 m/s） at 850-hPa were maintained,the 700-hPa was the convergence area of wind speed,and the 500-200-hPa was the divergence area.The strong convergence in lower troposphere,strong divergence in mid-high troposphere and strong upward motion were formed in the whole troposphere;water vapor was mainly transported along the southwest path,and some of it came from the northwest.There was a water vapor transport belt near 55°N,and it moved from the east to the west,then from the north and the northwest to the south and then to the southeast.The highest value of water vapor flux along this transport belt accounted nearly 1/4 of the southwest water vapor.Multi-source vapor transport was the main cause of forming the historical infrequent heavy snowstorm in north Xinjiang.
出处
《干旱区研究》
CSCD
北大核心
2011年第2期282-287,共6页
Arid Zone Research
基金
中国沙漠气象科学研究基金(Sqj2008008)
科技支疆项目(200891129)
国家自然基金面上项目(40875010)
关键词
暴雪天气
水汽通量
环流特征
物理量场
新疆
snowstorm
water vapour flux
circulation feature
physical scalar field
Xinjiang
