2017年河套地区一次暴雪天气过程分析

The process of Hetao area snowstrom in 2017

利用常规气象资料、FY-2C卫星云图和鄂尔多斯多普勒雷达资料,对2017年2月20—21日内蒙古河套地区的暴雪天气过程进行分析,结果表明:此次暴雪天气是在两脊一槽的环流形势中,高空槽、低层切变线与低空急流配合地面倒槽产生的;高低空急流耦合,为降雪天气的发生提供动力条件,低层700h Pa低空急流源源不断的将南海水汽输送至河套地区上空,为降雪天气的发生提供水汽条件;卫星云图上显示,强降雪主要发生在明亮密实的盾状云区,高低空急流与云区一一对应;雷达回波强度整体偏弱且稳定,但持续时间近12h,长时间的停留是此次暴雪天气发生的主要原因,回波顶高度基本位于6km以下,低层有暖平流进入,反映出此次降雪过程为稳定的层状云降雪。

Using conventional meteorological data, FY – 2C satellite image data and the Ordos doppler radar data, snowstrom weather process of Hetao area in Inner Mongolia on February 20th -21th, 2017 was analyzed. The resauts show that the snowstrom weather is upper trough in the circulation situation of two ridges a slot, low-rise shear line and low level jet with ground inverted trough ; the coupling effect of Upper and Low level Jet provide power for the beginning of snow weather conditions; the 700hPa low-level jet stream over the south China sea water vapor transport to the Hetao area, provide moisture conditions for snow weather happened; mainly in satellite cloud images showed the heavy snowfall with bright and dense cloud area, and high and low jet with different cloud area; intensity weaker overall and stable radar echo, long time lasting below 6km the echo top height and low-level warm advection, refects this snowstrom process to the stabilize stratiform cloud of snow.