2021年12月一次寒潮天气过程诊断分析

Diagnostic Analysis of a Cold Wave Weather Process in December 2021

摘要: 利用NCEP再分析资料、实况资料对发生在我国2021年12月的一次寒潮天气过程中环流形势、相关物理量进行分析，并重点分析了对东三省的影响。结果表明，此次寒潮天气过程有一定的极端性，使我国大部分地区出现较大幅度的降温，并伴随不同程度的雨雪天气。200 hPa强西风急流区覆盖我国大部，高空动量下传作用较为显著，500 hPa上表现为“两槽一脊”型，槽线不断东移南下，并与南支槽带来的大量暖湿气流交汇，共同作用下造成此次寒潮过程中的雨雪天气冷暖平流相互作用促进了冷暖气团的交汇，为降温以及降水过程提供了有利条件，在500 hPa上正涡度中心与高度场上的低值中心相对应。

Abstract: Using NCEP reanalysis data and live data, the circulation situation and related physical quantities of a cold wave weather process in December 2021 in China were analyzed, and the impact on the three northeastern provinces was analyzed. The results show that the cold wave weather process has a certain degree of extremeness, so that most areas of China have a significant cooling, accompanied by different degrees of rain and snow weather. The strong westerly jet region at 200 hPa covers most of China, and the downward momentum transfer at high altitude is more significant. At 500 hPa, it shows a “two troughs and one ridge” type. The trough line continues to move eastward and southward, and intersects with a large number of warm and humid air flows brought by the southern branch trough. Under the joint action, the cold and warm advection interaction of rain and snow weather in this cold wave process promotes the intersection of cold and warm air masses, which provides favorable conditions for cooling and precipitation processes. At 500 hPa, the positive vorticity center corresponds to the low value center on the height field.