中国东部地区降水季内变化的季节锁相

SEASONAL INTERLOCK OF THE INTRASEASONAL VARIATIONS OF RAINFALL IN EAST CHINA

用１９５４—１９８３年５—８月的逐日降水资料分析了中国东部地区降水的气候特征，并讨论了它同东亚季风季节内变化的联系。结果发现，江淮梅雨同华南夏季风降水都具有季节锁相特征，前者呈单峰分布，后者呈双峰分布。同时，降水量的季内变化均具有２０—２５天的周期振荡特征。江淮流域降水的峰值和华南地区的第一个峰值主要受副热带季风影响，同夏季风的季节性北进和加强有关，华南地区第二个降水峰值受南海热带季风影响，与同期西太平热带气旋的活动密切相关。

Based on the daily rainfall data of May-to-August from 1954 to 1983, this paper analyzes the climatic characteristics of precipitation in East China and discusses their association with seasonal variations of the East Asian monsoon.It is found from the analysis that both the Jianghuai (the Yangtze and Huaihe river basins) mei-yu and South China summer monsoon rain have seasonal interlock characteristics; the former shows a single peak dustribution while the latter displays a double peak distribution. Meanwhile, the intraseasonal variations of precipitation in both areas show a periodic oscillation of 15-25 days. The peak value of precipitation in the Yangtze and Huaihe river basins and the first peak value in South China are mainly affected by the subtropical monsoon,i.e.they are associated with the seasonal northward advancnig and strengthening of the summer monsoon. The second peak value of precipitation in South China is influenced by the South China sea tropical monsoon and closely related with the tropical cyclone activities in the corresponding period.