黄河流域降水要素的周期特征分析

ANALYSIS ON PRECIPITATION CYCLES IN THE YELLOW RIVER BASIN

依据黄河流域32个气象站点1951—2003年的月降水数据,应用最大熵谱分析法(maximum entropy method,MEM),分析了该流域降水变化的周期特征,探讨了影响降水周期特征的可能成因.结果表明,黄河流域降水序列明显存在着60a的代际尺度,14、25a的年代际尺度和3、9a左右的年际尺度变化周期.不同时间尺度、不同地区的降水周期也具有一定的差异性,说明了不同地区降水周期分布的复杂性.降水变化周期特性的存在既可能受到海-气相互作用的制约和影响,又可能与太阳活动密切相关,其具体影响机制有待进一步分析.

On the basis of the long-term monthly precipitation series at 32 weather stations in the Yellow River basin from 1951 to 2003, the precipitation cycles are analyzed by using the Maximum Entropy Method （MEM）, and the possible affecting factors, which drive the precipitation changes, are investigated. The results show that the precipitation in the Yellow River has decadal, inter-decadal and inter-annual oscillations like 60, 25, 14 and 9, 3 a. Precipitation cycles in different regions with various time scales are different. These changes are related to some possible physical processes such as the mutual action of sea and atmosphere, solar activities, and so on.