非降水性水分观测及其对陆面水分的贡献

The land surface process is one of the key aspects of regional climate change and even global climate change in the semi-arid region, and the land surface water process is the most active factor. Therefore, acquisition of accurate land surface water data is crucial for understanding the mechanism of land surface water processes and improving land surface model simulation. However, It is not good to describe the contribution of non-rainfall water is one of the important reasons for the unsatisfactory simulation results of the land surface model in present. This project will conduct non-rainfall water observation experiments in Dingxi, a typical semi-arid region of China, and integrate data of lysimeters, eddy correlation instruments, dry deposition and micro-meteorological observation, to study different elevations and the “edge effects” of lysimeters the effect of non-rainfall water formation; to study the contribution of non-rainfall water on land surface water in semi-arid area. The influences of soil moisture, evapotranspiration and latent heat on semi-arid area were evaluated by the land surface process model. This project has important significance in revealing the role of non-rainfall water in the land surface water process in the semi-arid area, which helps to deepen the understanding of the water cycle process in the semi-arid area and improve the relevant simulation of the water balance in the land surface process model.

半干旱区陆面过程是区域乃至全球气候变化的关键环节之一，其中陆面水分过程又是最活跃的部分。因此获得精确的陆面水分数据，对于认识陆面水分过程机理、提高陆面模式模拟至关重要。然而目前不能很好的描述非降水性水分的贡献是陆面模式的模拟结果不够理想的重要原因之一。本项目拟在我国典型半干旱区定西进行非降水性水分观测试验，综合蒸渗仪、涡动相关仪、干沉降数据及微气象观测的数据，研究不同高度、蒸渗仪“边缘效应”对非降水性水分的影响；研究半干旱区非降水性水分对陆面水分的贡献并通过陆面过程模式评估其对半干旱区土壤湿度、蒸散、潜热的作用。揭示非降水性水分在半干旱区陆面过程中的意义。本项目为改进非降水性水分的观测提供事实依据，有助于加深对半干旱区水分循环过程的认识，改善陆面过程模式中对陆面水分相关量的模拟。

陆面水分是半干旱区关键因子，对生态、作物有重要影响。本项目通过观测试验、理论分析等多种研究方法，首先分析了陆面观测主要仪器测量误差，为后续研究提供数据保障；其次建立了非降水性水分分量的判识方法，该方法不仅适用于干旱半干旱区，适用于湿润地区；随后系统分析了半干旱区非降水性水分分量的综合特征，揭示了非降水性水分的气候影响因子及环境影响因子；阐明了半干旱区非降水性水分对陆面水分循环的贡献，发现半干旱区非降水性水分对水平衡的贡献可以达到10%。还揭示了非降水性水分对半干旱区主要作物的影响，发现非降水性水分在非季风期对作物尤其重要。接着研究了不同气候区露水形成，阐述了不同高度非降水性水分对蒸发的贡献，发现不同高度非降水性水分对蒸发的贡献大小差异显著。同时也揭示了半干旱区非降水性水分对地表能量的贡献。最后总结了露水凝结模型的发展并指出了未来的研究方向。另外还从全球视野研究了全球季风区的气候、趋势、地表潜热通量和感热通量的主导模式及其对季风和降水的响应。总结了季风过渡带陆气相互作用的特点。项目在国内外专业期刊上发表研究论文8篇，其中被SCI收录2篇，EI收录1篇。获得实用新型专利1项，参与编写出版专著1部。获得省部级1等奖1项。1人入选甘肃省“陇原人才”；1人入选甘肃省气象局高层次科技创新人才计划“首席专家”。另外项目成果作为主要亮点工作之一申报了2022年甘肃省科技进步奖。通过本项目的研究，对半干旱区非降水性水分特征及其形成机制有了更为深入的理解和认识，可望为区域数值模式的发展提供支撑，为应对干旱灾害提供支撑。