降水和植被变化对龙川江径流量的影响

The Influence of Precipitation and Vegetation Change on the Runoff of Longchuanjiang River

基于龙川江大峡谷进出口水文控制站楚雄站和小黄瓜园站的长系列水文资料和流域森林盖度变化资料,结合小波分析方法,对降水、植被与径流量变化间相互关系以及径流量各时间尺度准周期变化的本质和形成机制进行了研究。结果表明:研究区降水量序列存在2 a、4 a和14.5 a左右的主周期,径流量序列具有2 a、4 a、6 a和22a左右的主周期;其中径流量低频振荡所反映的是总径流中来自于壤中水径流和存在于裂隙中的地下水径流的准周期变化,而高频振荡反映的是总径流中来自于地面径流的准周期变化;径流量的年内变化和年际高频振荡主要是由降水量变化所引起的,而径流量序列6 a和22 a的主周期是由土壤和裂隙对降水量序列4 a和14.5 a的主周期滞后放大作用所形成的,径流量序列4 a的主周期是由干热河谷特殊自然地理环境所形成的;径流量与降水量间相互关系在1969年左右发生了突变。

The paper is based on long series hydrologic data and the percentage of forest cover change data about Chuxiong hydrometric station and Xiaohuangguayuan hydrometric station of Longchuanjiang gorge. Wavelet analysis and statistical analysis are used to study on the interrelation among precipitation,vegetation and runoff variation, and they are also used to study the essence and generation system about quasi-periodic change of different timescale runoff volume. The result indicate that the study region＇s precipitation series exists 2 a,4 a and 14.5 a quasi-prime period, runoff volume series exists 2 a,4 a, 6 a and 22 a quasi-prime period, among them, nmoff volume＇ s low frequency oscillation reflects the quasi-periodic variation about the runoff comes from soil and the groundwater runoff exists in rifts, high frequency oscillation reflects the quasi-periodic variation about the surface runoff. Seasonal variation and annual high frequency oscillation of runoff are mainly caused by precipitation change. Runoff series＇ quasi-prime period around 6 a and 22 a is owing to the forming of soil and rifts＇ magnifing the precipitation series 4 a and 14.5 a prime period, runoff series＇ 4 years quasiperiod is formed by the special physical geographical environment. There is a sudden change of relationship between runoff and precipitation in 1969.