2016年1月22－26日影响海南岛一次强寒冷天气过程分析

为了深入了解强冷空气影响下海南岛的天气变化特征，进一步提高对强冷空气影响过程预报准确率，利用海南省区域自动站资料、常规天气观测资料以及NCEP/NCAR 2.5°×2.5°一日四次再分析资料，采用天气学原理和动力学诊断分析方法，对2016年1月22—26日影响海南岛一次强冷天气过程进行分析和总结。结果表明，此次强冷天气过程是由于极地涡旋分裂南下，同时乌拉尔山高压脊强烈发展使冷空气在横槽聚集，横槽前部等高线阶梯形势明显，并伴有明显负变高和冷平流，从而有利横槽转竖南压引导强冷空气向南爆发。强冷平流是造成海南岛出现强烈降温的主要原因；另外，由于低纬地区短波槽活跃，短波槽前暖湿气流与南下冷空气共同作用造成降水。

A Severe Cold Weather Process Affecting Hainan Island in 2016

To investigate the characteristics of weather change in Hainan Island under the influence of strong cold air and further improve the prediction accuracy, based on regional automatic station data of Hainan, conventional observation data and NCEP/NCAR 2.5°×2.5° 4-times daily reanalysis data, and with the synoptic principle and the dynamic diagnosis, the authors analyzed a severe cold weather process affecting Hainan Island during January 22-26, 2016. The results showed that: the polar vortex split toward the south, the ridge in the Ural Mountains fiercely developed so that the cold air could gather in the transverse trough, in front of the transverse trough, the gradient of geopotential height was quite large, and the negative variation of the height was obvious, so was the cold advection, these above mentioned conditions were favorable to revising the transverse trough and moving southwards , which could guide the outbreak of strong cold air southward. The strong cold advection was the main reason of sever cooling in Hainan Island, on the other hand, the shortwave trough was quite active in low latitude area and the warm wet current in front of that could interact with the southward cold air and caused the precipitation.