石羊河上游水文过程对气候与土地利用变化的响应

The security of basin water resources has become a major factor in restricting local and global socio-economic sustainable development. Since the 1960s, due to the impact of the global climate change and the human factors, especially a unreasonable land utilization, the primary vegetation has been severely damaged in the upper reaches of the Shiyang River Basin, and its function of water conservation has been declining rapidly, leading to the development of local socio-economic and the security of water resources in the middle and lower reaches of the River Basin facing severe challenges. Therefore, since 1999, the state has implemented a series of ecological restoration projects for reversing degradation of ecology and getting rid of the dilemma of water resources. However, due to the lack of scientific evaluation of its effectiveness, we are still unable to discern the problems and put forward a comprehensive management system, which is in line with the local situation and has the lowest cost, including the theoretical system and technical system. Based on the existing research and field experiment, by using the method of "experiment + model", the temporal and spatial characteristics of the climate change and the evolution of land utilization type in the upper reaches of the Shiyang River Basin in recent 30 years is analyzed; the process of hydrological for response to the process of climate change and change of land utilization is researched; the formation mechanism of process of hydrological and evolution of water resources is revealed in the upper reaches of the mountain; the single and interactive hydrological effects of climate and land utilization change is explored; the hydrological effects of various governance measures is assessed comprehensively, and according to the change of climate in the future, the theory and the framework of practice of the coordinated development of environment and economy are constructed in the upper reaches of Shiyang River Basin.

受全球气候变化和不合理土地利用方式的影响，石羊河上游原生植被曾遭到严重破坏，水源涵养功能下降，使当地社会经济的良性发展和流域中、下游地区的水资源安全面临严峻挑战。为此，从1999年开始，国家实施了一系列生态恢复工程，但由于缺乏对流域水文过程演变机制的充分理解及生态恢复工程生态水文后效的科学评价，成为政府进一步制定有效恢复措施及土地利用结构优化的瓶颈。因此，本项目拟在已有研究和野外实验的基础上，应用”试验+模型”相结合的方法，分析近30年石羊河流域上游地区气候变化和土地利用方式演变的时空特征，研究水文要素对气候以及土地利用变化的响应过程，揭示上游山区水文过程演变的形成机制，探索气候和土地利用变化所具有的单一及其交互水文效应，综合评估各项治理措施的生态水文后效，为石羊河流域土地利用规划和水资源的合理配置提供科学依据。

本项目在已有研究和野外监测的基础上，应用同位素、水化学技术与模型模拟相结合的方法，从以下几个方面对对石羊河上游水文过程及其对气候和土地利用变化的响应规律进行了探索和分析，基本把握了石羊河上游水文过程演变规律及驱动机制，具体内容如下：（1）建立了石羊河流域气象、水文和社会经济数据库。（2）气候变化研究。对石羊河流域降水、极端降水、极端气温及风速等主要气象要素进行深入分析，探明了石羊河流域近60年气候变化特征及其对全球变化的响应规律。（3）云下二次蒸发及水气来源对降水同位素的影响研究。应用同位素技术、拉格朗日模型以及雨滴蒸发模型对石羊河上游降水同位素特征、云下二次蒸发和水汽来源进行了深入分析，探明了水汽来源与云下二次蒸发对降水同位素影响的时间变化规律。（4）径流变化及归因分析。深入分析石羊河流域近60年径流变化过程及其对气候和土地利用变化的响应，明晰了流域径流演变规律，并揭示了其对气候和土地利用变化的响应机制。（5）土壤水分研究。对石羊河上游土壤水同位素特征及水分来源进行深入分析，探明了不同土层土壤水分来源、运移规律以及植被在土壤水再分配过程中的作用。（6）景观格局与河流水化学关系研究。分析景观格局对河流水化学的影响，揭示了不同空间尺度土地利用景观格局对河流水化学的影响机制。（7）干湿变化及干旱传播过程研究。分析石羊河上游气象干湿、水文干湿、土壤干湿的时空变化特征，探明了气象干旱向水文干旱、土壤干旱的传播规律及影响因素。研究成果为石羊河流域土地利用规划和水资源的合理配置提供了科学依据，部分成果已被应用到武威市国土空间规划。