【作者】 杨新；

【导师】 延军平；

【作者基本信息】 陕西师范大学 ， 自然地理学， 2003， 硕士

【摘要】 在全球气候变化的背景下，不同地区如何响应是当前区域研究工作的重点内容。目前国内外关于河流水文系统对全球变化的响应的研究较多地集中在流域径流量的特征变化上，范围上则是宏观研究大区域或者小流域或者整个国家范围内径流量的多少及趋势，对于一个中尺度区域内河流径流量序列变化的原因探讨较少。国内虽有一些衡量人为因素对径流量影响程度的研究，但由于所处地区自然条件大不相同，所以目前尚无公认的评价人类活动因素在径流量变化原因中所占比重的模型可资借鉴。所以人类活动因素影响下河流径流量变化模型及模拟还有待于针对不同地域、不同时空尺度做进一步的深化研究。 本文在当前河流径流量变化特征及其驱动原因研究背景的基础上，针对陕甘宁地区，建立天然径流量预测模型，模拟人类活动干扰下河流径流量的天然恢复值。实测值与预测值的差值就可以认为是人为因素所起的作用。选用陕甘宁地区的无定河、马莲河和清水河年径流量实测记录，应用多元回归方程并结合数理统计方法，以及地理信息系统空间分析方法，对陕甘宁地区河流径流量变化规律及驱动力因子进行了初步分析。 研究得到以下几点有意义的结论： 1．陕甘宁地区处于对全球气候变化较敏感的中纬度地区，是东亚夏季风边缘带，气候干旱不稳定，其主体部分为黄土高原中部的丘陵沟壑区，是世界上水土流失最严重的地区，生态环境十分脆弱，目前气候暖干化趋势明显。对该区地表水资源的研究具有极为深刻的现实意义。 2．河川径流来源于降水，影响因素有蒸发等自然因素及人类活动造成的人为因素。河流径流量在自然和人为因素的共同影响下而变化，变化特征复杂，趋势具有不确定性。而地区的持续发展离不开水资源，因此需要掌握河川径流的变化特征、趋势及驱动因素，从而为科学合理地制定区域开发和治理战略与决策提供理论依据。 3．40多年来，在气候暖干化的背景下，陕甘宁地区地表水资源变化总趋势为减少，表现为自1950年代末以来河川年径流量的显著减少倾向，而且贫水化也日趋严重。实地考察结果也证实了该结论。 4．陕甘宁地区河流径流量总的变化趋势为减少，但各条河流变化情况不同。无定河年径流量无论总体变化趋势还是各个阶段都为显著减少；马莲河和清水河年径流量在1986～1988年前后两个阶段内的变化趋势都为显著减少趋势。 5．通过多元回归方程预测自然状态下陕甘宁地区河川年径流量，对比实测径流量来分析人为因素对径流量的影响程度。 人为因素使无定河流域径流量减少量越来越大。人类活动的驱动力占总驱动力的份量从1980年代末的不到20O，上升到1990年代的30O。在1997年人为影响程度最大，其值达到40％左右。无定河流域河川径流的人类活动影响程度在显著上升。马莲河数据分析表明，在 1980年代末到 1990年代初，马莲河流域人类活动对径流量的影响有正有负，即人为因素的影响尚不明确，但从 1990年代中期以来，人类活动的减流负面作用不断增强，2000年达到阶段最大值。清水河流域的天然径流量预测结果与无定河和马莲河流域不同，大部分预测值低于实测值，其中原因为其年径流量的数据为恢复过的数据，所以这并不意味着清水河流域人类活动绝对的增加了其径流量，但其变化趋势说明了人为影响程度的加重。 6．本文初步分析了全球气候变化下陕甘宁地区河流年径流量的变化，对该变化的成因作了初步探讨。陕甘宁地区河流年径流总量明显减少，蒸发是影响径流量变化的最敏感的气候因子，但流域蒸发量序列的变化趋势、特征和河流年径流量不一致。流域河川径流来源于降水，全球变化是河流径流量变化的背景。在这个背景下，人为因素的影响程度在明显增强，可以认为人类活动因子是河流径流演变的主要驱动因子。更多还原

【Abstract】 Under the background of global climatic change, the responses in different areas have been recognized as a global issue. At present domestic and international research work of river hydrology system responses to global climatic change focus on the change character of river runoff, and the study scope is mostly macroscopic of nation or large district, and few study involve in the reason of local river runoff change. Although there are several studies on influence degree of human factors on river runoff, generally acknowledged model to appraisal the weight of human activities has not show yet at present because the regional natural conditions differ widely. So further study on model of influence of human activities on river runoff change and simulation in different regions is necessary.Global climatic change would cause the response of ecosystem. In arid and semi-arid regions such as Shaanxi-Gansu-Ningxia region, what is the response of regional river runoff? Would it cause river runoff to increase or reduce? How are the trends of these changes? This paper tried to discuss the reason.In this paper, the characteristics and tendency of annual runoff changes of Wudinghe River, Malianhe River and Qingshuihe River are analyzed. Moreover,the aid of gray interrelation analysis and the plural regression model are applied to discuss the reason of runoff decrease and abrupt changes.For over 40 years, under the background of climatic warming, river runoff of Shaanxi-Gansu-Ningxia region has showed a generally reduction trend. Observation on the spot has verified this conclusion, too. There is also a difference in all rivers in this region. Annual runoff of Wudinghe river reduced notably in both general tendency and periodic change. Annual runoff of Malianhe river show a decline tendency in the period both between 1955-1986 and 1987-2000. Annual runoff of Qingshuihe river showed a similar tendency to Malianhe river in the period between 1956-1987 and the period between 1988-2000.Firstly established plural linear regression model to estimate the river runoff uninfluenced by human. Compare with the record of hydrology examinition stations,then analyze the influence degree of human factors, namely the diference of the two river runoff account.Human factor have made the river runoff reduce more and more and they are becaming the driving force. The account of human influence weights less than 20% in the end 1980’s, 30% in 1990’s. Human influence’s degree reached the maximum in 1997. The influence of human activities on river runoff rises notably.Analysis proved that impact of human activities on Malianhe river runoff is still uncertain from the end of 1980’s to 1990’s. Since middle period of 1990’s, river runoff has been reduced by human activities constantly, and maximum in 2000. The degree of human activities’ influence in Qingshuihe river runoff aggravate by time.Therefore, this paper, taking the Shaanxi-Gansu-Ningxia region as a case area, preliminary discussed the ecosystem’s responses under the background of climatic change. The decline of river runoff indicates the obvious trend of environmental aridity in the region. The impact of human activity on the runoff decline is obviously strengthening, and has already occupied a leading position in recent years.更多还原