空中水汽输送是全球水循环中最为活跃的一个环节，水汽输送的特性影响着降水的形成和分布，进而对全球各地区水资源条件和生态环境产生深远的影响。但是，目前我们仍缺少相关的模型工具从水文水循环视角来描述空中水汽输送的格局和结构。针对这一问题，本文提出了一种利用数学中的图结构对复杂的水汽输送格局进行描述的概念性模型，即水汽输送网络。 水汽输送网络的研究以追踪每个水汽单元的拉格朗日运动轨迹(迹线)为基础。为了建立蒸发和降水之间通过水汽输送形成的对应关系，我们提出了单位迹线及其水量的概念，计算了每条迹线对降水的实际贡献以及水汽的来源位置，使得迹线上原本模糊的水量输入输出关系清晰化，解决了水汽输送中水量的含义及如何计算的问题。本文使用ERA-Interim再分析数据集计算了三江源地区主要降水事件以及全球强降水事件的水汽输送单位迹线。 迹线是对单一水汽输送事件的路径的具体表达，但空中水汽输送的宏观过程是由相互关联的大量水汽输送路径共同体现的群体性规律，为此，本文提出了一种半结构化散点聚合法，将大量混乱的水汽输送迹线转化为统一的网络结构。该方法在转换过程中保持了水量的概念，使得网络中的元素能够直接表征水汽的蒸发、降水、输送这些实际物理量，从而建立起水汽输送网络。基于这套方法，本文提取了面向三江源地区的水汽输送网络，分析结果表明，网络的结构特征与该地区地貌特征高度吻合，并且本地水汽对降水的贡献率约为9.15％，与已有研究的相关结论基本一致。针对全球强降水事件建立的全球水汽输送网络进一步展示了这种网络模型能为水汽输送宏观格局及其时空变异性的研究提供定量分析能力。 另外，文本还研究了空中水循环系统中形成的大尺度相对独立区域，定义为空中流域。发现在水汽输送网络的理论框架下，如何划分空中流域的问题可以用图论中的图分割方法解决。全球尺度的空中流域划分结果反映了各地区水汽输送机制的不同，符合大气环流规律。 本文提出的水汽输送网络模型物理含义明确，水量关系清晰，方法的可拓展性强，可利用图论的数学工具来实现丰富的应用延伸，有望为空中水汽输送规律的研究提供一种新的工具。 关键词：空中水汽输送；图论；拉格朗日迹线；水汽输送网络；空中流域

 Moisture advection and transport in the atmosphere is the most active process in the global water cycle. The characteristics of water vapor transport affect the formation and distribution of precipitation, and exert a far-reaching influence on water resources and ecological environment all over the world. However, there is a lack of quantitative tools to describe the pattern of water vapor transport from the perspective of hydrological cycle. To address the problem, this thesis proposes a conceptual model, namely, the water vapor transport network, to use the mathematical graph structure to describe the complex water vapor transport pattern. The research of the water vapor transport network is based on tracking the Lagrangian trajectory of each water vapor parcel. In order to establish clear correspondence between water vapor evaporation and precipitation along each trajectory, we proposed the concept of unit trajectory and the concept of water vapor quantity along it, as well as the method to calculate the actual contribution of water vapor to precipitation on each trajectory and to identify the source locations of water vapor, thus, providing clear linkages between water input and output. Using ERA-Interim reanalysis data, we calculated the unit trajectories related to the precipitation over Sanjiangyuan region and strong rainfall events all around the world. The macroscopical pattern of water vapor transport is represented by the collection of massive trajectories. In this thesis, a semi-structured scatter points aggregation method is therefore proposed to convert all trajectories into a unified structure of water vapor transport network that maintains the water mass conservation during the conversion. The water vaper network can represent the actual physical relationship among evaporation, precipitation and transportation of water vapor. Using the proposed method, we established the water vapor transport network flowing into the Sanjiangyuan region, and analyzed the water vapor sources and transport characteristics for this region. We found that the structure of the network is highly related with geomorphic characteristics, and the contribution rate of local evaporation to precipitation is about 9.15%, basically consistent with the relevant conclusions from previous studies. Moreover, the global water vapor transport network related to worldwide strong rainfall events also demonstrates that this network model is suitable for quantitative analysis of macroscopical patterns and spatiotemporal variability of water vapor transport. We also studied the large-scale regions that are relatively independent in the atmospheric water cycle system, termed atmospheric basins. We concluded that within the theoretical framework of water vapor transport networks, the extraction of atmospheric basins can be done with a graph partitioning method in graph theory. The division of global atmospheric basins yields a result that reflects the differences in water vapor transport mechanisms for various regions and is meteorologically interpretable. The model of water vapor transport network proposed in this study has a clear physical meaning, holds quantitative relationships of water mass, and is also extensible. Powerful mathematical tools of graph theory can help to realize diverse applications, providing a new tool for the study of atmospheric water vapor transport. Key words: atmospheric moisture; graph theory; Lagrangian trajectory; atmospheric water vapor transport network; atmospheric basins