RAPID: The Mechanisms Driving Extreme Precipitation in Atmospheric Rivers with an Integrated Stable Isotope and Aerosol Chemistry Approach

这项快速反应研究（Rapid）奖是为了收集2015-16年强厄尔尼诺事件期间加州的降水数据。研究人员将研究大气河流，这是来自热带的水汽羽流，它增强了风暴，给美国西海岸带来了大量降水。该项目将通过增加降水稳定同位素数据的额外测量地点来补充正在进行的这些事件的研究。降雨的同位素分析可以让我们深入了解水的来源和相变历史，这让科学家们更好地了解强降雨事件是如何以及为什么开始的。更好地了解大气河流事件期间的降水将有助于改进天气和气候模式。这项工作还将帮助培养下一代科学家，让不同群体的本科生参与数据的收集和分析。课题组计划利用水和水蒸气的稳定同位素定量评价水汽的起源和降水，并解决三个主要科学问题：1)气溶胶与降水量、效率和相位之间的关系是什么？2)极端降水事件的稳定同位素特征是什么，宏观和微观尺度动力学是造成极端降水事件的原因？3)极端降水事件的水分来源是什么？这些来源在风暴中是如何变化的？这个RAPID项目将补充现有的与CALWATER-2现场项目相关的观测工作，包括额外的测量站点和测量水蒸气实时稳定同位素的仪器。活动结束后，PI团队将分析大约1500个水样，而合作者将分析冰和云凝结核化学。天气尺度和反轨迹分析也将使用WRF模型进行。

This Rapid Response Research (RAPID) award is for the collection of precipitation data in California during the 2015-16 strong El Nino event. Researchers will study atmospheric rivers, which are plumes of moisture from the tropics that enhance storms and bring substantial precipitation to the west coast of the United States. This project will complement an ongoing study of these events by adding additional measurement locations for stable isotopes of precipitation data. Isotopic analysis of rainfall can provide insight into the source and the phase change history of water, which gives scientists a better idea of how and why heavy rainfall events are initiated. A better understanding of the precipitation during atmospheric river events should help improve weather and climate models. The work will also help to train the next generation of scientists by including a diverse group of undergraduate students in the collection and analysis of data.The research team plans to quantitatively evaluate the origin and rainout of moisture with the stable isotopes of water and water vapor, and address three main scientific questions: 1) What are the relationships between aerosols and precipitation amount, efficiency and phase? 2) What are the stable isotope signatures of extreme precipitation events and which macro-and micro-scale dynamics are responsible for producing them? and 3) What are the moisture sources of extreme precipitation events and how do these sources change within storms? This RAPID project will complement an existing observational effort related to the CALWATER-2 field program by including additional measurement sites and an instrument to measure real-time stable isotopes of water vapor. After the campaign the PI team will analyze around 1500 water samples while collaborators will analyze ice and cloud condensation nuclei chemistry. Synoptic scale and backtrajectory analysis will also be performed with the WRF model.