昌吉州一次强降雪天气过程诊断分析

Diagnostic Analysis of a Heavy Snowfall Weather Process in Changji

摘要: 利用常规地面与高空观测资料、自动站逐时降水资料、NCEP1˚ × 1˚再分析资料以及探空资料，对2017年12月27~28日昌吉州出现的一次强降雪天气过程进行分析。结果表明此次强降雪发生在低空西北冷湿急流与中层较强西南急流叠加并维持的有利环流背景下。由地面冷高、中低压、低层切变线、地面冷锋及地形强迫抬升等多尺度系统共同作用下造成的。此次过程前期有两条水汽输送带，一条由阿拉伯海北部的水汽沿西南气流东北上进入中亚，一条沿偏西水汽输送路径补充进入北疆，低空西北急流对此次大降雪天气水汽贡献最大。

Abstract: Using conventional ground and altitude observation data, hourly precipitation data from automatic stations, NCEP1˚ × 1˚ reanalysis data and sounding data, a heavy snowfall weather process in Changji from 27 to 28 December, 2017 was analyzed. The results showed that the heavy snowfall occurred under the favorable circulation background of the superposition and maintenance with the low-level northwest cold-wet jet and the middle-level strong southwest jet. It was caused by the combined action of multi-scale systems such as surface cold high, middle-low pressure, low-level shear line, surface cold front and forced topographic uplift. There were two water vapor conveyor belts in the early stage of this process. One was from the northern Arabian Sea to Central Asia along the northeast of the southwest airflow, and the other was from the west to the north of Xinjiang. The greatest contribution was the northwest jet at low altitude to the water vapor during this heavy snowfall.