冷涡背景下不同类型强对流天气的成因对比分析

结合地理分布将中国北方高空冷涡划分为东北冷涡（120°-145°E，35°-60°N），华北冷涡（100°-130°E，30°-45°N）以及东蒙冷涡（100°-130°E，40°-55°N）三类，根据2000-2018年NCEP/NCAR 1°×1°再分析资料和日降水资料对19 a冷涡个例进行筛选对比，统计分析三类冷涡的活动规律，利用动态合成分析方法分析三类冷涡的结构和降水特征。结果表明：在490例高空冷涡个例中，遗漏的冷涡个例有2个，重复的个例有13个，剩下475例个例都能较好的被选出和归类，给出的三类冷涡定义较为合理。东北冷涡和东蒙冷涡在全年皆可生成，而华北冷涡在12月和2月没有发现。东北冷涡在4、5月生成最多，在3月和8月生成较少。华北冷涡在5月生成最多，冬季生成较少。东蒙冷涡在5、6、9三个月生成较多，在2、3和11月生成较少。对三类冷涡的动态合成分析表明：在结构方面，考察位势高度、温度、涡度、和等熵位涡分布，得到东北冷涡平均强度最强，东蒙冷涡次之，华北冷涡最弱；在降水方面，冷涡强度最强的时段，冷涡降水主要出现在高空急流出口区以北，对应有强的高层辐散。由于低层湿度分布以及水汽输送强度的不同，三类冷涡的降水大值中心位置有所差别，并且华北冷涡平均降水强度最大，东北冷涡次之，东蒙冷涡相对较小。

Climatology of warm season cold vortices in East Asia:1979-2005

Based on geographical distribution, the North China cold vortexes are divided into three categories:Northeast China Cold Vortex (120°-145°E, 35°-60°N), North China Cold Vortex (100°-130°E, 30°-45°N) and East Mongolia Cold Vortex (100°-130°E, 40°-55°N). According to NCEP/NCAR 1°×1° reanalysis datasets and daily precipitation datasets from 2000 to 2018, the cold vortex cases in 19 years are screened, the activity rules of the three kinds of cold vortexes are statistically analyzed, and the structure and precipitation characteristics of the three kinds of cold vortexes are analyzed by dynamic composite analysis method. The results show that in the 490 cases of high-altitude cold vortexes in 19 years, 2 cases are missed, and 13 cases are repeated. The remaining 475 cases can be well selected and classified, and the definitions of three types of cold vortexes are reasonable. Northeast Cold Vortex and East Mongolian Cold Vortex can occur throughout the year, while North China Cold Vortexes are not found in December and February. Northeast Cold Vortexes are found mostly in April and May, and also in March and August with less frequency. North China cold vortexes are found mostly in May and less frequently in winter. In May, June and September, there are more cold vortexes generated in east Mongolia, while there are fewer in February, March and November. Dynamic composite analysis is used to analyze the three types of cold vortices. In terms of structure, the distribution of potential height, temperature, vorticity, and isentropic potential vortices show that the average strength of the Northeast China Cold Vortex is the strongest, followed by the East Mongolia Cold Vortex, and the North China Cold Vortex is the weakest. In the period when the cold vortex intensity is the strongest, the cold vortex precipitation mainly appears in the north of the outlet area of the upper jet, with strong divergence. Due to the differences in the distribution of low-layer humidity and the intensity of moisture transport, there are differences in the location of large precipitation centers of the three types of cold vortexes. The North China Cold Vortex has the largest mean precipitation intensity, followed by the Northeast Cold Vortex, and the East Mongolia Cold Vortex has relatively weak precipitation.