摘要
利用１９５１ 年到１９９６ 年华北地区１７ 个站的月降水资料，分析了华北地区夏季各月降水的年代际变化特征。结果表明：６ 月降水量较少，且在年代际变化上没有表现出减少趋势；７ 月降水量较多，年代际变化较大，８０ 年代最少；８ 月的降水量在年代际变化上表现出线性减少的趋势并呈准１０ 年周期的振荡。７ 月和８ 月的降水量均在６０ 年代中期和从７０ 年代末到８０ 年代初有两次明显的减少。根据７ ，８ 月降水不同的年代际变化特征，我们利用合成分析方法考察了与华北地区旱、涝的年代际变化相关联的中高纬地区大气环流异常，指出：７ 月降水量的变化不仅与７ 月大气环流异常有关系，而且还对８ 月大气环流异常有影响。这一结果说明，在华北地区夏季降水量的变化与北半球中高纬大气环流异常之间的关系中，前者影响后者似乎是更为主要的方面。
The features of interdecadal variations of precipitations in various months of summer in North China are analyzed by using the observed data of summer monthly precipitations from 1951 to 1996 at 17 stations in North China. It is shown that the precipitations in each month have different features. In North China, the precipitation in June was the smallest and does not exhibit a decreasing trend in the interdecadal variations,but the precipitation in July was the largest with a large interdecadal variability and reached its minimum in the 1980's. There are a linear decreasing trend and a quasi ten years oscillation in the interdecadal variations of precipitations in August. Both precipitations in July and August in North China remarkably decreased in the middle 1960's and at the end of 1970's.According to the different features of precipitations in July and August, the atmospheric circulation anomalies in the middle and high latitudes associated with the interdecadal variaitons of droughts and floods in North China are examined by using composite method. The analyzed results suggested that the interdecadal variations of precipitation in July not only were associated with the atmospheric circulation anomalies in July, but also had an important impact on the atmospheric circulation anomalies in August. In the relationship between the variations of summer precipitation in North China and the atmospheric circulation anomalies in the middle and high latitudes, the impact of the former on the latter may be more dominant.
出处
《高原气象》
CSCD
北大核心
1999年第4期509-519,共11页
Plateau Meteorology
基金
中国科学院"九.五"重大应用基础研究项目
关键词
年代际变化
大气环流异常
华北地区
降水
Precipitation Interdecadal variation Atmospheric circulation anomaly
