Development and Application of In-Situ Measurement of Water Vapor Isotopes For Hydrological And Ecological Research

0229343李旭辉该建议书包括三项任务。在任务I中，我们将与坎贝尔科学公司合作。设计并建立了一套用于连续原位测量大气水汽中HDO和H218O同位素比值的TDL系统。该仪器将与耶鲁大学和其他地方使用的冷阱方法进行测试。在任务二中，我们将使用新的TDL系统来确定从地球表面蒸发并与低层大气交换的水蒸气中的同位素比率。同位素通量比将用微气象梯度扩散法和涡动累积法确定。准确确定通量比的能力在两个科学领域是必不可少的：植物-水关系和古气候。 在任务III中，我们将获得并解释地面空气中稳定水同位素比的连续时间序列，包括边界层阵风，阵雨，日周期，锋面气旋和季节。我们的连续时间序列的优点是，我们将能够观察到在不同时间尺度上运行的各种大气过程。我们预计，同位素方法将是非常敏感的细微变化，在水蒸汽冷凝和蒸发历史的一个airmass.Successful完成这些任务将打开一个新的“窗口”的水文循环，特别是涉及相变的过程中的水。该项目还将通过促进学术界和私营企业之间的伙伴关系，以及为水文学、生态学、气象学和全球变化研究的基础设施提供新的仪器，对社会产生更广泛的影响。

0229343Xuhui LeeThe proposal includes three tasks. In Task I, we will work with Campbell Scientific Inc. to design and build a TDL system for continuous and in-situ measurement of HDO and H218O isotope ratios in atmospheric water vapor. The instrument will be tested against a cold-trap method, used at Yale and elsewhere. In Task II, we will use the new TDL system to determine the isotopic ratio in water vapor evaporating from the earth's surface and exchanging with the lower atmosphere. The isotope flux ratio will be determined with the micrometeorological gradient-diffusion and eddy accumulation methods. The ability to determine the flux ratio accurately is essential in two fields of science: plant-water relationships and paleo-climate. In Task III, we will obtain and interpret continuous time series of stable water isotope ratio in surface air on time scales including boundary layer gusts, rain showers, the diurnal cycle, frontal cyclones and seasons. The advantage of our continuous time series is that we will be able to observe a variety of atmospheric processes operating on different time scales. We expect that the isotopic method will be extraordinarily sensitive to subtle changes in water vapor condensation and evaporation history of an airmassSuccessful completion of these tasks will open a new "window" on the hydrologic cycle, especially to processes involving phase changes of water. The project will also generate broader impact on the society by promoting partnership between the academia and a private industry and by contributing new instrumentation to the infrastructure for research in hydrology, ecology, meteorology and global change.