2018年冬季塔城盆地两次致灾暴风雪天气对比分析

A Comparative Analysis of Two Blizzards Causing Disasters in Tacheng Basin in the Winter of 2018

摘要: 利用常规观测资料对2018年11月24~26日、11月30~12月2日发生在塔城盆地的两场区域性致灾暴风雪天气的成因进行对比分析，结果表明：两次暴风雪天气都是在上游主导系统强烈发展，中高纬度环流经向度迅速加大，脊前西北风带携带冷空气不断南下，推动其下游的西西伯利亚低槽东移南下过程中产生的强冷平流、动量下传、气压梯度力、高层辐散，低层辐合造成的抽吸作用，使得上升运动得到发展加强，“三支气流”在塔城盆地汇合，为暴风雪天气的发生发展提供了热力和动力条件。暴风雪天气中高低空形势、物理量条件的不同导致两次暴风雪天气出现差异。

Abstract: Based on conventional observation data, the causes of regional disastrous snowstorms were compared and analyzed in Tacheng basin that happened during 24th - 26th on November, from November 30th to December 2nd, 2018. The results show that the two snowstorms occurred when leading system strongly developed in the upstream, the meridional of circulation in middle and high latitudes increased rapidly, and the cold air continued to move southward along northwest wind belt which was in front of the ridge, so that the West Siberian trough moved toward the southeast. Based on the strong cold advection, momentum downward transmission, pressure gradient force, high-level divergence and low-level convergence, ascending motion have been developed and strengthened. There were “three airstream” converging in Tacheng basin, providing thermal and dynamic conditions for the development of snowstorm weather. It was different from high and low control situation and physical quantity condition, so the snowstorm weather characteristics were different too.