2016年11月下旬一次强寒潮天气过程诊断分析
Diagnostic Analysis of a Strong Cold Wave in the Late November of 2016

本文利用实况观测资料及再分析资料，对发生在2016年11月20日~25日天气过程的全国性寒潮天气过程，从气候背景以及部分物理量场进行了诊断分析，结果表明此次寒潮天气过程是属于横槽转竖型，槽后冷空气迅速东移南下以及西太副高异常北抬，是这次寒潮天气过程的直接影响系统；通过对温度平流和假相当位温的分析，发现本次寒潮天气过程的剧烈降温是由于强冷平流促使西北路冷空气迅速东移南下造成的，而对K指数以及垂直速度的分析表明，由于西太副高的异常北抬输送了大量的暖湿气流并与冷空气交汇，使得大气层结不稳定在华北、西南、华南等地区形成了大范围的降水过程。
Based on the actual observation data and reanalysis data, this paper makes a diagnostic analysis of the national cold wave weather process from November 20 to 25, 2016 from the climate background and some physical quantity fields. The results show that the cold wave weather process belongs to the horizontal trough to vertical type, and the cold air behind the trough moves eastward and southward rapidly and the western Pacific subtropical high moves northward abnormally, which is the direct influence system of this cold wave weather process. Through the analysis of temperature advection and pseudo-equivalent potential temperature, it is found that the severe cooling of this cold wave weather process is caused by the strong cold advection, which promotes the rapid eastward and southward movement of the cold air in the northwest road. The analysis of K index and vertical velocity shows that due to the abnormal northward lifting of the Western Pacific subtropical high, a large amount of warm and humid air is transported and intersected with cold air, which makes the atmospheric stratification unstable and forms a large-scale precipitation pro-cess in North China, Southwest China, South China and other regions.