山东春季降水的时空变化特征分析

Analyses on Spring Rainfall Spatial and Temporal Changes of Shandong Province Using EOF

根据山东省81个地面站1961-1998年共38年的降水资料,应用自然正交函数展开(EOF)方法,分析了山东省38年春季月、季降水量的时空变化特征.根据降水方差累积贡献率和空间分布特征,指出前3个典型场基本能反映山东省春季季降水分布的主要特征,其贡献率高达81.30%,据此得出山东省春季降水分布类型:总体一致型、东南-西北差异型和西南-东北差异型.山东春季降水空间分布可分为4个区,南部区:日照、临沂、枣庄及济宁;半岛区:烟台、威海、青岛和潍坊东部;西部区:荷泽、聊城;北部区:德州、滨州、东营、济南、泰安、莱芜、淄博和潍坊西部.同旱(涝)是山东春季各月降水的基本型.山东春季易出现干旱,春季降水存在明显的年际变化,有4.8～6年的振荡周期.

Based on the precipitation data at 81 surface stations of Shandong Province during spring of 1961-1998, EOF method is used to analyze spring precipitation of the Province in this article. According to total accumulation variance contributing rate and space distribution characteristics, the first three typical fields （whose contributing rate is 81.30%） can indicate the main characteristics of Shandong spring rainfall distribution. There exists three patterns for the precipitation： The same anomaly in whole Province, different anomalies between both in southeast and northwest and in southwest and northeast directions. There are four areas about Shandong spring rainfall： AreasⅠ （Rizhao, Linyi, Zaozhuang and Jining） is the south area, Area Ⅱ（Yantai, Weihai, Qingdao and the east in Weifang） is the east area, Area Ⅲ（Heze and Liaocheng） is the west area, Area IV （the other ones） is the north area. The same anomaly in whole Province is a base pattern in every month during Shandong spring. Drought disaster easily occurs during Shan- dong spring. There is a 4.8-6 year oscillation periods during Shandong spring precipitation.