Long-term trend of precipitation in the Yellow River basin during the past 50 years
Long-term trend of precipitation in the Yellow River basin during the past 50 years
复制标题
DOI：
10.11821/yj2006010004
复制
发表时间：
2006-02
影响因子：
3.3
通讯作者：
Z. Xu;N. Zhang
中科院分区：
文献类型：
--
作者：
Z. Xu;N. Zhang
以往的一些研究表明，黄河下游断流是由于降水量减少和工农业过度消耗黄河中下游水资源造成的，分析降水量的长期变化趋势有助于黄河流域水资源的合理利用。Mann-Kendall检验是一种基于秩的非参数方法，已被广泛用于估计水文气象时间序列中长期趋势的重要性，如水质，流量，温度，本文分析了黄河流域降水量的长期变化趋势，并对黄河流域的气候变化趋势进行了预测。对年、月降水量时间序列进行了Kendall检验，并将线性回归结果与Mann-结果表明，77个测站中有65个测站年降水量呈下降趋势，4、7、10月对年降水量的下降趋势贡献最大，且典型月份的长期趋势空间分布不同，除1月外，其余月份均呈下降趋势。2、3、6月趋势值均为负值，呈减少趋势，除夏季外，黄河上游北方35度以南地区降水量呈增加趋势，除渭河上游和呼和浩特地区外，黄河流域降水量呈减少趋势，通过对Mann-Kendall检验和线性回归检验两种方法估计结果的比较，（12月至次年2月），经Mann-Kendall法检验无趋势，远多于线性回归法检验，除7月和12月外，其他月份两种方法估计的趋势值大小也基本相同，线性回归法估计的趋势值绝对值均大于Mann-Kendall法估计的趋势值。
Some of previous studies showed that the drying-up of the lower Yellow River was resulted from decreasing precipitation and excessive industrial and agricultural consumption of water from the middle and lower Yellow River.The analysis for the long-term trend of precipitation is helpful for the rational use of water resources in the Yellow River basin. The Mann-Kendall statistictest is a rank-based,non-parametric approach and has been widely used to estimate the significance of long-term trends in the hydro-meteorological time series such as water quality,streamflow,temperature,and precipitation.The long-term trend of precipitation in the Yellow River basin was analyzed in this paper and the Mann-Kendall test was applied to annual and monthly precipitation time series.The linear regression was compared with the results obtained by using Mann-Kendall test.The results show that 65 of 77 stations exhibited downward trend for annual precipitation.April,July and October contributed the most of the decreasing trend of annual precipitation,and the spatial distribution of long-term trend for typical months is different.In all months except January,February,March and June,the values of trend are negative,exhibiting the decreasing tendency.In all seasons except summer,there is a similar increasing trend in the upstream of the Yellow River,south of the northern latitude 35 degrees.Except the regions in the upstream of the Weihe River and Hohhot the precipitation showed a decreasing trend in the Yellow River basin,especially in the downstream of the Yellow River.Comparing the results estimated by two methods,the Mann-Kendall test and linear regression test,the stations in winter(from December to next February),without trend tested by Mann-Kendall method,are much more than those tested by linear regression method,and the number of stations with trends tested by both methods is similar in other seasons.The magnitude of trend estimated by both methods is also similar in all months except July and December,and the absolute values of trend estimated by linear regression method are greater than those estimated by Mann-Kendall method.