Abstract:

Low-temperature spring flooding over Northeast China refers to a meteorological phenomenon characterized by persistently low temperatures and excessive precipitation in spring, primarily from March to April, which severely hinders spring agricultural operations, particularly plowing and sowing. In this paper, based on monthly temperature and precipitation data of 104 national meteorological stations in Northeast China during 1961-2020, and the monthly reanalysis data of the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), combined with the sea surface temperature and the atmospheric circulation indices with significant correlation, a case study is carried out. The low-temperature spring flooding events and their judgment indexes are defined, and the multi-factor synergy of temperature, precipitation and other factors at the cross-seasonal scale, as well as the influence mechanism of atmospheric circulation and sea surface temperature anomalies in the same period and in the early stage are preliminarily revealed. The results show that persistent cold and rainy conditions in spring are key contributors to the occurrence of such events, and the abnormal increase of accumulated precipitation in autumn in the previous year is the key factor resulting in severe low temperature and spring flood events. In addition, the negative phase of the Arctic Oscillation (AO) in the preceding winter, the stronger-than-normal Siberian High in spring, and the active Northeast China cold vortex and cold waves are important dynamical conditions. Furthermore, abnormal warming of sea surface temperatures, especially associated with El Niño events in the previous autumn and winter, is in favor of the occurrence of low-temperature spring flooding. These events are often followed by alternating drought and flood conditions in Northeast China, typically manifesting as a “drought-flood-drought” pattern during late spring to early summer, midsummer, and winter, respectively.

Key words: low-temperature spring flooding events, Siberian High, North Atlantic Oscillation, Arctic Oscillation, El Niño-Southern Oscillation

摘要：

东北地区低温春涝事件是指春季（主要为3—4月）出现的温度持续偏低、降水偏多的气象现象，严重影响春耕春播顺利进行。本文利用1961—2020年东北地区104个国家级气象站逐月气温、降水资料和美国国家环境预报中心/美国国家大气研究中心（National Center for Environmental Prediction/National Center for Atmospheric Research，NCEP/NCAR）逐月再分析资料，结合海温和相关显著的大气环流指数，通过个例分析，定义了春季低温春涝事件及其判定指标，初步揭示了跨季节尺度下温度、降水等多因子协同作用，以及同期、前期大气环流和海温异常的影响机制。结果表明，春季的持续低温多雨是关键影响因素，而前一年秋季累积降水异常偏多是形成严重低温春涝事件的关键因子；前期冬季北极涛动（Arctic Oscillation，AO）呈负位相、春季西伯利亚高压偏强，东北冷涡和寒潮活跃是重要动力条件；前一年秋冬季发生厄尔尼诺（El Niño）事件时，海温异常有利于东北地区低温春涝事件的发生；当低温春涝事件发生后，东北地区当年春末夏初、盛夏和冬季易出现“旱、涝、旱”交替的现象。

关键词: 低温春涝事件, 西伯利亚高压, 北大西洋涛动, 北极涛动, ENSO