辽宁中东部地区一次降雪天气过程诊断

Diagnosis of a Snowfall Process in Central and Eastern Liaoning

利用地面自动站气象要素资料、NCEP再分析资料对2017年1月26—27日辽宁省中东部地区降雪过程进行了诊断分析,探讨了天气形势特征以及物理量场与降雪落区的对应关系。结果表明,此次降雪梯度性明显,降雪时间短、强度大。高空冷槽东移南下过程中发展加深配合蒙古气旋形成与加强共同作用,导致此次降雪的发生。辽西地区低层弱辐合、中层辐散、高层辐合的配置形式不利于抽吸作用,上升运动不强烈。另外,系统过境时垂直方向有下沉运动以及整个过程水汽含量较低,这些不利条件可能与此次过程辽西地区无降雪有关。中东部地区暴雪的产生主要是由低层系统强烈的动力抬升作用所致。中东部降水位置与垂直上升运动位置相对应。850 hPa相对湿度大值区间移动速度较快,这可能与此次降雪过程强度强、持续时间短有关。

Based on the meteorological elements of ground automatic station and NCEP re-analysis data, the snowfall pro- cess in central and eastern Liaoning Province from January 26 to 27, 2017 was diagnosed and analyzed, and the re- lation between weather situation and physical quantity field and snowfall area were discussed. The results showed that the snow was charactered by obvious gradient, short time and high intensity. The development of high-altitude cold trough combined with Mongolian cyclone formation and strengthening resulted in the occurrence of snowfall. The snowfall in the central and eastern Liaoning was mainly caused by the strong dynamic u- plift of the lower system, and the pre- cipitation location corresponded to the vertical upward movement.