东北夏季降水的气候及异常特征分析

采用统计分析的方法对近50 a东北夏季降水的气候及异常特征进行了分析。结果表明:东北夏季降水空间分布很不均匀,除三江平原地区外东北大部7月降水最多;夏季全区出现较重干旱的概率大于较重雨涝,旱灾更为突出,其中辽西是较重旱涝频发的地区;近50 a夏季降水没有明显变干或变湿的倾向,而是具有阶段性旱涝交替特征,存在27、11 a左右的年代际尺度周期和3~6 a左右的年际尺度周期变化;6月旱灾几率大,易形成6~7月的连续干旱,7月易形成区域性特大涝灾,6月和8月在年代际尺度上具有反位相变化的特征。

Analysis of Climate and Anomaly Features of Summer Precipitation in Northeast China

Statistic methods are used to analyze the climate and anomaly characteristics of summer precipitation in Northeast China in recent 50 years.Results indicate that precipitation is unevenly distributed.Rains occurs mostly in July over most parts of Northeast China except the Sanjiang Plain.The occurrence probability of severe droughts is greater than that of severe floods,which indicates that drought disasters are more frequent than floods.Floods/droughts occur more frequently in the west part of Liaoning Province than in the other regions of Northeast China.Generally speaking,the wet/dry trend isn't obvious in recent 50 years,but there exists the alternative flood/drought variation feature with the interdecadal periods being about 27 and 11 years and the interannual periods being 3 to 6 years.Droughts occur more frequently in June;there often occur persistent droughts from June to July,and the regional severe floods are usually reported in July.Th opposite phase is found in the interdecadal scale variation between June and August.