Characteristics of Precipitation Anomalies in Northeast China during the Summer of 2019

Abstract

Using the NCEP/NCAR reanalysis data and the daily precipitation data of 237 meteorological stations in Northeast China (NEC), the characteristics of summer precipitation anomalies in 2019 are investigated, and the possible influence mechanism is also preliminarily discussed. Our statistical result shows that the overall precipitation of NEC in the summer of 2019 (∼ 448.3 mm) was remarkably higher than that in normal years (from 1981 to 2018, with the climate mean summer precipitation of 358.0 mm), in which the positive anomaly percentages of Heilongjiang Province and Songhua River basin were approximately 53% and 40%, respectively. The unusually high precipitation was the largest since the year 1961. During that period of time, the 500 hPa geopotential height field was distributed in a “.- .+ .-” pattern from west to east in the northern high latitudes, and the NEC region was fully controlled by a significant negative height anomaly field; the western Pacific subtropical high at low latitudes was significantly larger, stronger and more westerly than normal, and the ridge position was more southerly, which is conducive to the northward advance of summer monsoon and the transport of water vapour to NEC. Furthermore, the extremely active northeast cold vortex and northward typhoon are the dominant reasons for the abnormally increased precipitation over NEC.