东北冷涡分类及其对内蒙古东部降水的影响OACSTPCD

Utilizing daily precipitation data from 119 national meteorological observation stations in Inner Mongolia during June to August from 1981 to 2022,along with NCEP/NCAR daily reanalysis data,the interannual and decadal variation characteristics of the Northeast Cold Vortex and its classification impact on precipitation in eastern Inner Mongolia were analyzed.The results indicate that the frequency of the Northeast Cold Vortex occurrences was significantly higher than the average before 1992,followed by a significant decrease until a rising trend emerged after 2003,with the past decade experiencing a higher frequency of occurrences.The Northeast Cold Vortex was classified into 10 types,among which the eastward movement of the central vortex to the northeast was identified as the most anomalous cold vortex type leading to excessive precipitation in the east,followed by the eastward movement of the central vortex as the next most anomalous type.The East Asia region exhibited a"high in the north,low in the south"circulation pattern,with eastern Inner Mongolia located in a negative potential height anomaly zone,centered in the southern part of the east.The Ushan and Ehai blocking highs were anomalously strong,as was the subtropical high,placing the eastern region of Inner Mongolia under cyclonic circulation control.Low-level moisture flux convergence,in conjunction with the low-latitude cross-equatorial flow,guided the west Pacific moisture transport to the eastern region,representing the main circulation configuration type responsible for the anomalously high precipitation in the east.