南海夏季风爆发对广西6月暴雨的影响

利用1961—2020年广西地面气象观测站逐日降水资料、NCEP/NCAR再分析资料，研究了南海夏季风爆发对广西6月暴雨的影响。结果表明，当南海夏季风爆发偏早时，东亚大槽显著偏强，中高纬度地区经向环流增强；华南沿海西南风显著偏强，配合中高纬度偏强的经向型环流引导北风南下，南北风在广西上空交汇；印度洋到海洋性大陆热带季节内振荡(MJO)处于对流活跃位相，且向东移动明显，低频对流带在西南季风引导下向广西输送；广西上升气流显著偏强，暴雨日数偏多。反之，暴雨日数偏少。

The impact of the onset of the South China Sea summer monsoon on rainstorm anomalies in June over Guangxi

Using composition, EOF, correlation and other methods on the daily precipitation data from Guangxi surface meteorological observation stations from 1961 to 2020 and NCEP/NCAR reanalysis data, the impact of the onset of the South China Sea summer monsoon on the heavy rainfall in Guangxi in June is studied, revealing the causes of the climate anomalies on the heavy rainfall days.The results show that the East Asian trough is significantly stronger when the onset of the South China Sea summer monsoon is earlier, and the meridional circulation in the middle and high latitudes is strengthened.Additionally, the southwesterly wind along the South China coast is significantly stronger, which is combined with the strong meridional winds in the middle and high latitudes.While the Madden-Julian oscillation (MJO) from the Indian Ocean to the oceanic continent is in the phase of convection enhancement, moving significantly eastward with the low-frequency convection belt being transported to Guangxi under the guidance of the southwest monsoon, the northerly wind, guided by the circulation, moves southward and the north-south wind converges over Guangxi.Also, it indicates that the updraft is significantly stronger over Guangxi, as indicated by the increased frequency of rainstorm days and, on the other hand, the relatively low number of rainstorm days.