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以黄土高原昕水河流域为对象,采用有序聚类等数理统计方法,诊断了近60a来实测径流的变化及其阶段性特征,在此基础上,分析了不同阶段实测径流与气候要素之间的响应关系,初步揭示了径流演变的驱动机制。结果表明:近60a来昕水河流域实测径流量以1965年和1979年为分割点总体呈现阶段性减少趋势,其中,21世纪以来减少尤其明显。不同阶段的年降水、径流关系有一定差异,相比而言,汛期(6—10月份)的月降水量与径流量具有相对较好的相关关系,非汛期(11—5月份)的月降水径流关系点群散乱。积雪及融雪对河川径流量的影响存在±5℃阈值,当气温介于该阈值区间,气温变化对河川径流影响较大。昕水河流域汛期产流受高强度降水支配,非汛期径流量以地下径流和融雪径流为主。人类活动对河川径流的影响有增大趋势。
Taking Xinshui River basin of the Loess Plateau as an example, this paper uses ordinal clustering and other mathematical statistics to diagnose the change of the measured runoff in the past 60 years and the characteristics of its phases. On the basis of this, the actual measured runoff and climate factors at different stages The relationship between the initial response to the evolution of runoff revealed the driving mechanism. The results show that in the past 60 years, the measured runoff in Xinshui River Basin shows a decreasing trend in stages from 1965 to 1979, of which the decrease is particularly obvious since the 21st century. The annual precipitation and runoff in different stages are different. In contrast, the monthly precipitation and runoff in flood season (June-October) have a relatively good correlation, and the monthly precipitation in non-flood season (November-May) Runoff point group scattered. The impact of snow and snowmelt on the runoff of the river has a ± 5 ℃ threshold. When the temperature is within the threshold range, the change of temperature has a great influence on the river runoff. The runoff in the flood season of Xinshui River Basin is dominated by high-intensity precipitation. The non-flood season runoff is dominated by underground runoff and snowmelt runoff. The influence of human activities on the runoff of rivers has an increasing trend.