典型草原生态干旱评估方法与影响机制

Arid is an important adversity factor that restricts the sustainable development of the eco-environment, society and economy in the grassland area. Typical grassland located in the arid and semi-arid area has extremely sensitive and fragile ecological environment, with obvious drought trend, causing especially prominent problems such as water resource shortage and desertification. At present, the common drought quantitative assessment method is not enough to consider the natural environment factors, so it is difficult to guarantee the reliability of the regional grassland drought simulation results. Selecting typical grassland of Inner Mongolia east-central as study area, starting from the connotation of ecological drought, this project considers the coupling effect of meteorological conditions, water supply, soil hydrothermal condition and growth condition of vegetation on drought. Based on the perspective of hydrology, this subject project will synthetically apply the technologies of observational experiment, statistical test, mechanism analysis and model simulation, constructing the multi-dimensional coupling model of meteorology-water resources-vegetation-soil. It uncovers the multi-attribute characters and the rules of evolution changes across time and space in eco-drought situation by quantitatively simulating the water and thermal global state in typical steppes. An integrated application of observation statistical tests, mechanism analysis and model simulation technology will use to construct the meteorological-water-vegetation-soil multi-dimensional coupling model. Benefitting from the quantitative simulation of typical grassland hydrothermal global state, many characteristic properties of ecological drought and succession law across time and space scales will be obtained. Exploring the main influencing factors and mechanism at spatial and temporal differentiation of typical grassland ecological drought can not only enrich and improve the method system of quantitative evaluation of ecological drought, but also provide theoretical basis and technical support for formulating countermeasures against and against drought in the region.

干旱化是制约草原地区生态环境社会经济可持续发展的重要逆境因素，位于半干旱地区的典型草原，水资源匮乏，生态环境极其敏感脆弱，由于不合理的开发利用，致使干旱化与荒漠化加剧。目前普遍使用的干旱定量评估方法对自然环境要素考虑不足，难以保障温带高原草地干旱模拟结果的可靠性。本项目选择内蒙古中东部的典型草原作为研究区，从生态干旱的内涵视角，以气象条件、水资源供给、土壤水热状态和植被生长状况对干旱的耦合作用为研究重点，基于生态水文学，综合运用观测试验、统计检验、机理分析、模型模拟等技术，构建气象-水资源-植被-土壤多维耦合模型，定量模拟典型草原水热全局状态，揭示生态干旱的多特征属性和跨时空尺度演替规律，科学识别生态干旱演变的影响机制，探索典型草原生态干旱时空分异的主要影响因素及其作用机理，研究可丰富和完善生态干旱的定量评估方法，亦可为草原防旱抗旱制定科学对策提供理论基础与技术支撑。

干旱是世界上危害最广泛、最严重的自然灾害之一。全球气候变暖加剧了水循环，导致极端气候事件频发。干旱已成为限制我国北方草原畜牧业发展和生态系统健康的重要因素。选取位于内蒙古高原中东部的典型草原为研究对象，以草原型内陆河——锡林河流域为重点研究区，针对流域关键气象-水文-生态过程进行综合观测试验，结合统计检验、机理分析、模型模拟等手段，围绕典型草原生态干旱评估方法与影响机制开展了系统研究。聚焦气象条件、水资源供给、土壤水热状态和植被生长状况对流域干旱的耦合作用，分析了草原生态干旱主控因子的时空演变特征，并在气候变化和过度放牧两个方面对其驱动机制进行探讨；面向变化环境下草原生态系统干旱的定量评估方法，发展了非一致性干旱的定量研究方法，突破了流域多尺度干旱综合评估的难题，形成了基于多维耦合模型的典型草原生态干旱评估方法；进一步在不同时空尺度上识别了草原干旱的时变规律、空间格局和传播特征；并尝试探索了草原型流域干旱演变与传播的主导环境驱动及其作用机理。项目执行期间，在国内外学术期刊发表论文14篇（其中SCI论文9篇，CSCD论文5篇），授权实用新型专利1项，申报计算机软件著作权6项，联合培养博士毕业生1人、硕士毕业生2人。本项目研究成果能丰富和完善非一致性干旱研究理论，可为草原防旱抗旱、水资源利用和生态健康等提供理论参考与技术支持。