摘要
应用Mann -Kendall秩统计法和回归分析法 ,检验时间序列上的年降水趋势 ;应用一阶自相关分析法 ,对沙坡头地区多年降水持续性特征进行统计分析。结果表明 ,5a滑动平均曲线所对应区间 196 7— 1972年以及1977— 1982年降水量大于多年平均值 ,而 1983— 2 0 0 0年降水量滑动平均值低于多年平均值的趋势明显。 195 5—1970年的分析时段内 ,降水量每连续递减两年后 ,将稍有回升 ,但总体上趋于下降。从滑动平均计算值来看 ,年降水分布存在时间序列上的非随机因素潜在振荡 ,5a滑动平均值突出了以年为时序单位的降水振荡模式。干旱时段的延长通常在多雨年之前或之后发生 ,尤其在 1978年经历高峰降水以后 ,直至 1985年 ,区内干旱时段的延长颇为显著。
Shapotou area is belonged to a steppe desert z on e with a mean annual precipitation (MAP) of 191\^1 mm (during 1955\_2000). The s tability of artificial-natural vegetation system in this area depends closely o n the annual precipitation character. Meanwhile, every precipitation event comes along with dust storm, which will contribute to the crust formation on the fixe d sand dunes. For understanding the ecological function of this special phenomen on, the study on distribution, trends and variability of precipitation in Shapot ou region is necessary. Time series of annual precipitation were examined for di stribution and trends using Mann-Kendall rank statistic, and for variability us ing first order autocorrelation analysis. Results indicate that the annual preci pitation in the 5-year moving value is above mean annual precipitation during t he periods of 1967\_1972 and 1977\_1982, respectively. From 1983 to 2000, it is obviously that the annual precipitation is below MAP. The precipitation value in creased after it was decreased in two successive years in 1970s, but the trend i s declined in general. In the case by calculating moving means, here illustrated the 5-year moving mean accentuates the oscillatory pattern suggested by the an nual time series. The drought spells prolonged after the peak precipitation in 1 978, and it was terminated till 1985, which suggests the principle of prolonged dry spells usually precede or follow a precipitation season in desert region. In the transitional area of arid and semiarid region, Shapotou area is likely subj ected to the arid zone.
出处
《中国沙漠》
CSCD
北大核心
2001年第3期260-264,共5页
Journal of Desert Research
基金
中国科学院寒区旱区环境与工程研究所知识创新工程项目 (CACX2 10 0 3 1)
中国科学院沙坡头沙漠试验研究站开放基金(2 0 0 0 2 5 )
973项目子课题 (G2 0 0 0 0 4870 4)资助
