黄河流域降水演变规律研究

基于黄河流域及其周边地区1000多个水文气象站近50年的月降水资料所生成的整个流域及其29个三级区的面雨量过程，采用多种时间序列分析方法，研究了黄河流域降水的随机性、趋势性和周期性。结果表明：黄河流域各三级区降水量Hurst系数的分布范围在0.449～0．644之间，说明其具有长期弱相关性；Kendall秩次相关检验结果表明黄河流域降水减少的趋势性不明显，从三级区看，大通河享堂以上等7个三级区降水有一定的减少趋势；黄河流域降水的短周期为准3年周期，中长周期一般表现为l1年和22年左右的周期。

Study on Precipitation Evolution Law of the Yellow River Basin

The paper studies the randomness, tendency and periodicity of precipitation in the Yellow River basin by analytical methods of multi time series based on the data of mean areal precipitation process of the whole river basin and 29 Grade III regions generated by the last 50-year monthly precipitation of more than 1,000 hydrometeorological stations suited in the basin and surrounding area. The results show that the distribution range of precipitation Hurst coefficient of each Grade III region of the Yellow River basin is between 0.449 ~ 0.644, having long-term low correlation; the results of Kendall rank correlation examination show that the tendency of precipitation reduction of the Yellow River basin is not obvious and the precipitation of 7 Grade III regions above Hengtang on the Datong River has the trend of reduction and; the short period of precipitation of the basin is quasi-3-year period and usually medium-and-long range is about 11 years and 22 years.