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题名 河西内陆河山区流域基流过程研究
姓名 董薇薇
院系 资源环境学院
专业 水文学及水资源
学位名称 工学硕士
外文题名 The Research of Base Flow Process in Mountain Area of Hexi Island River Basin
第一导师姓名 魏霞
关键词 基流变化;河西内陆河;气候变化;冰冻圈变化
外文关键词 Base flow variation;Hexi island;climate change;cryosphere change
学科 工学
摘要 基流是河川径流的重要组成部分,也是干旱半干旱地区枯水季节最重要的水源。基流过程与气候变化和冰冻圈变化有着密切的联系。本文以河西内陆河山区的疏勒河、黑河和石羊河流域为研究对象,采用数字滤波法,基于日径流资料进行基流分割。在基流分割之前首先对滤波参数和滤波次数进行率定,对比确定滤波参数后估算了各流域的基流量,并以此为基础,分析了基流变化特征,进而从气候变化和冰冻圈变化两个方面探讨了基流变化的影响因素。通过上述研究,获得了以下主要结论:(1)河西地区基流量的空间变化为中部最多,西部次之,东部最少。(2)西部和中部基流量的年际波动比较剧烈,总体上均呈现增加的趋势,各流域基流指数的年际变化不大。(3)西部和中部夏秋两季的基流量有增加趋势,东部基流量减少,冬春季节基流量变化趋势比较稳定。(4)基流量的年际变化趋势与降水量基本相似,波动过程大体一致。基流量与夏季径流存在显著地相关关系。(5)降水是河西内陆河山区流域基流变化的主要影响因素,气温间接的影响基流的变化。气温升高会导致冰雪融水的增加和多年冻土的退化,冰川径流的增加有利于基流的补给,多年冻土退化增加了活动层厚度,减缓了冬季的退水过程,相应的增加了地下径流对河流的补给。
外文摘要 As an important component of runoff, base flow is the most important headwaters in dry season in arid and semi-arid regions. The process of base flow is closely related to climate and cryosphere changes. This article focuses on Shule river basin, Heihe river basin and Shiyanghe river basin in Qilian mountains of the Hexi island. Based on daily runoff data, the recursive digital filter is used for base flow separation. Before using this method to separate base flow, the parameter and number of filtering should be calibrated. Through the comparison, determine the filter parameter and calculated the base flow, and on this basis, analyzed the changes of base flow, and then the affecting factor on the changes of base flow from two aspects of climate change and cryosphere changes is discussed. Through the above research, following is the main conclusions:(1)The spatial variation of base flow value in Hexi island is gradually reduce from midland to west and from west to east. (2)The base flow inter-annual fluctuation of western and central regions are severe and overall shows increasing trend. The decadal variability of base flow index shows that at decadal scale, the proportion that base flow accounts for the runoff is relatively stable.(3)In general, the base flow value in summer and autumn at the western and central region of Hexi island have increasing trend and reduced in eastern. Base flow values are relatively stable in winter and spring.(4)Inter-annual variation trend and wave process of base flow is similar with precipitation. Analyzing the relationship between base flow variation and runoff in summer shows that there is significantly correlation between the two Precipitation is a major influence factor to the change of base flow in Hexi island and temperature is an indirect factor. Rising temperatures will lead to the increase of ice and snow melt and permafrost degradation. The increasing of glacial meltwater is good to base flow recharge. The degradation of permafrost increases activity layer thickness, slow down the recession process of runoff in winter and increases the supply from underground runoff to river.
研究领域 寒旱区水文水资源
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