基于稳定同位素技术的小尺度SPAC系统水分耗散规律研究

Researches on water dissipation in soil-plant-atmosphere continuum (SPAC) are regarded as one of the most famous and challenging tasks in hydrology, meteorology and earth sciences. There have been numerous studies on SPAC system in the world. And it will become more and more popular in the future. The purpose of this project is to improve the understanding in small scale SPAC system and clear the relative importance of partitioning evapotranspiration. The stable isotope compositions will be used to determine the mixing of transpiration and evaporation. Atmospheric water vapor, liquid water, soil and vegetation will be sampled for measurement of the concentration of stable isotopes. The samplings are going to take place in two different kinds of ecological system, grass and crops. The spatial scales are focused in this project are small. There are four tasks in this project. The first one is to separate evaporation from transpiration in grass ecological system according to stable oxygen and hydrogen isotopic composition of water. The second one is to separate evaporation from transpiration in crop ecological system using stable oxygen and hydrogen isotopes with different methods from the first task. After comparing the results from the first two tasks, we will move on to analyze the migration variations of oxygen and hydrogen isotopes of water from grass filed. The last task is to validation the results of evapotranspiration separation in crop system. The achievements of this study will be important to understand the principle of transformation among atmospheric water, surface water, soil water and groundwater. We believe that our findings will also be important to comprehend the hydrological cycle progress exhaustively and develop the hydrological and climate models efficiently.

土壤-植物-大气连续系统（SPAC）水分耗散规律研究一直是国内外水文、气象、地学界关心的焦点和难点问题之一，尤其是近年来随着地表物质迁移和能量交换研究的深入，SPAC系统水分耗散规律研究越来越受到人们的重视。本项目以水汽、液态水、土壤水以及植物茎秆和叶片等多种类型样品的氢氧稳定同位素测试分析为手段，以提高小尺度SPAC系统水分耗散规律的认知水平为目标，选取草地系统和农作物系统两种小尺度SPAC系统，分别研究其各自的水分耗散规律，以及水分循环各环节中氢氧同位素的迁移变化规律。主要开展以下四个方面的研究：（1）草地系统的蒸散组分结构识别研究；（2）农作物系统的蒸散组分结构识别研究；（3）草地系统氢氧同位素迁移变化规律及根系用水结构研究；（4）农作物系统蒸散组分结构识别成果验证研究。研究成果对于四水转化机制研究、水文循环过程精细考察、水文模型与气候模型开发等具有重要的科学意义。

土壤-植物-大气连续系统（SPAC）水分耗散规律研究一直是国内外水文、气象、地学界关心的焦点和难点问题之一，尤其是近年来随着地表物质迁移和能量交换研究的深入，SPAC系统水分耗散规律研究越来越受到人们的重视。本项目以水汽、液态水、土壤水以及植物茎秆和叶片等多种类型样品的氢氧稳定同位素测试分析为手段，以提高小尺度SPAC系统水分耗散规律的认知水平为目标，选取草地系统和农作物系统两种小尺度SPAC系统，分别研究其各自的水分耗散规律，以及水分循环各环节中氢氧同位素的迁移变化规律。主要开展以下四个方面的研究：（1）草地系统的蒸散组分结构识别研究；（2）农作物系统的蒸散组分结构识别研究；（3）草地系统氢氧同位素迁移变化规律及根系用水结构研究；（4）农作物系统蒸散组分结构识别成果验证研究。研究成果对于四水转化机制研究、水文循环过程精细考察、水文模型与气候模型开发等具有重要的科学意义。