【摘要】 认识区域水沙运移规律及其对气候和土地利用变化的响应能够为水土流失防治提供理论依据,是水土资源综合开发的重要前提.本研究以1963—2013年逐月实测气象、径流和泥沙资料为基础,结合20世纪80年代和2000年土地利用数据和归一化植被指数(NDVI)数据,采用Mann-Kendall趋势分析和突变检验方法,系统分析了西北干旱区典型小流域——小南川流域的气候和水沙长期变化特征,并识别了研究区土地利用及植被覆盖度变化特征.在对单要素变化充分解析的基础上,利用多元线性回归等方法,定量探讨了气候和土地利用变化对小南川流域水沙运移的影响机制,并明确了关键作用因子.结果表明:小南川流域气温向两极化发展,降水量逐渐增加,总体气候变化趋势朝向暖湿方向,极端气候事件发生频率增加,且在20世纪90年代发生突变后,其变化速度和程度均进一步加剧.自20世纪80年代以来,随着经济社会发展,流域内耕地和城镇扩张,林地增加,自然生态环境向良性发展.在土地利用和植被覆盖度变化的主导驱动作用下,流域径流量和输沙量分别以1.7×106m3·(10 a)-1和1.5×108kg·(10 a)-1的平均速率呈减少趋势.定量化研究结果揭示了植被覆盖度和月平均最高气温是影响该区径流变化的最关键因子,而植被覆盖度和日最大降水量是影响输沙变化的最关键因子.在当前气候变化背景下,生态修复是防止干旱区流域水土流失的最有效途径之一.更多还原

【Abstract】 Understanding regional water and sediment transport patterns and their responses to cli-mate and land use changes can provide a theoretical basis for the prevention and control of soil ero-sion, and is an important prerequisite for the integrated development of land and water resources.Based on monthly monitoring meteorological, runoff, and sediment data from 1963 to 2013, com-bined with the land use data in the 1980 s and 2000 and NDVI data, using the Mann-Kendall trendanalysis and abrupt change test method, we systematically analyzed the long-term variations of theclimate, runoff and sediment transport, with the changes of land use and vegetation coverage beingidentified in the Xiaonanchuan( XNC) River basin, a typical watershed in the Northwest aridregion. Based on the analysis of single element change, the impacts of climate and land use changeon water and sediment transport were quantified by the multiple linear regression analysis. Simulta-neously, the key action factors were identified. Results showed that air temperature was developingto the polarization, the precipitation increased gradually. A generally warm and wet tendency of cli-mate change and an increased frequency of extreme climate events were found in the XNC Riverbasin. Moreover, the speed and magnitude of climate change were intensified after the 1990 s, which was the abrupt change point of the climate. Since the 1980 s, with economic and social develop-ment, the area of arable land and built land expanded, that of the forest area increased, and theecological environments were improved in the XNC River basin. Under the dominant driving effectsof land use and vegetation coverage change, the runoff and sediment load gradually reduced with theaverage rate of 1.7×106 m3·(10 a)-1 and 1.5×108 m3·(10 a)-1, respectively. Quantifying theinfluence of land use and climate change on the water and sediment transport indicated that vegeta-tion cove-rage and mean daily maximum temperature were the two key factors affecting the runoffchange, while the vegetation coverage and maximum daily precipitation were the two key factorsaffecting the sediment load change. Under the condition of current climate change, ecological resto-ration could be one of the most effective ways to prevent water and soil losses in the arid area.更多还原