黄河源区积雪变化下的土壤湿度时空响应研究

The Yellow River source region is the important water conservation in the Yellow River basin, and has the prominent strategic significance in ecological environment security and economic and social development. In recent decades, snow change leads to the spatiotemporal pattern change of hydrology and water resources in the Yellow River source region, especially intensifies the heterogeneity of the soil moisture spatiotemporal distribution. In addition, as the lack of observation data, the reliability of analysis results on the spatiotemporal evolution rule of soil moisture under snow change reduced. For the scientific problem of the soil moisture spatiotemporal evolution mechanism affected by snowmelt under the influence of terrain, vegetation, and so on, this project will analyze the in-situ soil moisture dynamic change characteristics and the annual evolution rule of snow through the field observation experiment and multi-source data inversion technique. Constructing the unscented ensemble particle filter by improving the particle sampling method and probability distribution assumption, then obtain the multidimensional continuous soil moisture data with high accuracy in Yellow River source region by coupling the Common Land Model. Finally, construct the spatiotemporal statistical relationship between snowmelt and soil moisture, clarify the soil moisture annual distribution variation under snowmelt, and reveal the soil moisture spatiotemporal response mechanism under snow change in Yellow River source region. The results of the proposed study have important scientific significance to the analysis on hydrologic characteristics and the distribution of water resources in Yellow River source region.

黄河源区作为黄河流域重要的水分涵养地，在生态环境安全和经济社会发展等方面具有突出的战略意义。近几十年来，积雪变化导致了黄河源区水文水资源时空格局改变，特别是土壤湿度时空分布不均匀性加剧。加之源区观测资料匮乏，致使积雪变化下土壤湿度时空演变规律分析结果的可靠性降低。本项目针对在地形、植被覆盖等影响下，融雪对土壤湿度时空影响机制的科学问题，拟通过野外观测实验、星地多源数据反演技术，分析点尺度土壤湿度动态变化特征及积雪年际年内演变规律；改进粒子取样和概率分布假设方法，构建无迹集合粒子滤波同化技术，耦合通用陆面模式CLM4.0，获取黄河源区多维连续的高精度土壤湿度分布场；建立融雪量与土壤湿度的时空统计关系，阐明融雪下土壤湿度年际年内分布变化规律，揭示积雪变化下黄河源区土壤湿度的时空响应机制。研究结果对黄河源区水文要素和水资源分布规律分析等具有重要科学意义。

黄河源区作为黄河流域重要的水分涵养地，在生态环境安全和经济社会发展等方面具有突出的战略意义。近几十年来，积雪变化导致了黄河源区水文水资源时空格局改变，特别是土壤湿度时空分布不均匀性加剧。加之源区观测资料匮乏，致使积雪变化下土壤湿度时空演变规律分析结果的可靠性降低。本项目基于EnKF和无迹转移方程，提出了无迹加权集合卡尔曼滤波UWEnKF，及评估该方法的有效性，及分析土壤湿度时间变化和一维垂向分布变化；分析了土壤属性、降雨等变化对土壤湿度的影响；探讨了区域土壤湿度分布变化规律。研究成果对于提高土壤湿度模拟结果具有直接作用，对于黄河源区水文要素和水资源分布规律分析等.具有重要科学意义。在本项目资助下发表了第一资助SCI和中文核心文章各1篇，其它资助SCI文章3篇，EI文章1篇，中文核心1篇。获福建省水利学会第十五次（2017-2018年度）优秀学术论文一等奖。