Collaborative Research: EUREC4A-iso--Constraining the Interplay between Clouds, Convection, and Circulation with Stable Isotopologues of Water Vapor

合作研究：EUREC4A-iso——用水蒸气的稳定同位素体约束云、对流和环流之间的相互作用

• 批准号: 1937583
• 负责人: Joseph Galewsky
• 金额: $ 34.48万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-11-15 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1937583&HistoricalAwards=false
• 关键词: Collaborative; Research; EUREC4A; iso; Constraining

Low-level clouds over tropical oceans cool the earth's climate by reflecting sunlight back to space. In global climate models (GCMs) these clouds generally amplify greenhouse gas-induced warming, as warming reduces cloud cover and allows more sunlight to reach the surface, causing further warming. But the strength of this amplification varies considerably from model to model and contributes substantially to the large range of warming estimates from GCMs. Moreover, cloud simulations from fine-scale, small-domain models which explicitly represent low clouds show less reduction in cloudiness than GCMs, which represent low clouds indirectly through parameterizations. On the other hand, cloud cover in the fine-scale models can reduce significantly with warming if the low clouds organize into clusters, a behavior not captured in GCMs.Recent research suggests that low cloud sensitivity differences among GCMs, and between GCMs and fine-scale models, can be understood in terms of the various ways in which models balance the moistening and drying effects of precipitation, surface evaporation, turbulent mixing, and cloud updrafts and downdrafts over tropical oceans. This research has identified specific balances which lead to higher or lower cloud sensitivity to warming, allowing tests against observations to be made. New observations are required to conduct such tests.Work supported under this award collects observations of the isotopic composition of water vapor, raindrops, and sea water to examine the moistening and drying processes that determine low cloud properties and sensitivities. Ordinary water (H2O) consists of two hydrogen atoms and one oxygen-16 atom, but some water molecules contain atoms of the heavier isotopes deuterium, oxygen-17, and oxygen-18. Water molecules containing heavier isotopes condense more readily and evaporate more sluggishly than ordinary H2O. Thus air samples with the same humidity can have different concentrations of heavy isotopes depending on the processes through which that humidity came about. For instance, if the humidity level is set by the mixing of dry air above the cloud layer and moist air near the ocean surface, concentrations of heavy isotopes will generally be higher than if the same humidity level is established by condensing water out of moist low-level air. Water isotope data is collected as part of a field campaign with the acronym EUREC4A, for Elucidating the Role of Clouds-Circulation Coupling in Climate. EUREC4A is a multinational campaign led by the Max Planck Institute in Germany and the Laboratoire de Meteorologie Dynamique in France, with a deployment based in Barbados from January 20th to February 20th 2020. This award supports isotope sampling from two ships, an aircraft, and the Barbados Cloud Observatory. Data collection and analysis is combined with model simulations in a variety of ways. Much of the work involves models which simulate the distinct behaviors of heavy isotopes so that direct comparisons with isotopic data can be made.The research has broader impacts due to its potential for reducing uncertainty in GCM-based estimates of the severity of future climate change. The EUREC4A campaign also provides an opportunity to enhance international scientific collaboration, and the project provides field experience for two graduate students. Outreach to the public is conducted during the campaign through a blog, and the PIs have partnered with the New Mexico Museum of Natural History and Science to perform outreach through programs including the Young Explorers Summer Science Camp and the Junior Docent Program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在热带海洋上的低水平云通过将阳光反射回太空，使地球气候降温。 在全球气候模型（GCM）中，这些云通常会放大温室气体引起的变暖，因为变暖会减少云覆盖物并使更多的阳光到达地面，从而进一步变暖。 但是，这种扩增的强度因模型而异，并且对GCMS的大量变暖估计产生了很大的贡献。此外，明确表示低云的细尺度，小域模型的云模拟比GCMS显示出较少的云量，而GCMS通过参数化间接表示低云。 On the other hand, cloud cover in the fine-scale models can reduce significantly with warming if the low clouds organize into clusters, a behavior not captured in GCMs.Recent research suggests that low cloud sensitivity differences among GCMs, and between GCMs and fine-scale models, can be understood in terms of the various ways in which models balance the moistening and drying effects of precipitation, surface evaporation, turbulent mixing, and cloud updrafts and在热带海洋上的放流。 这项研究确定了特定的平衡，这会导致对变暖的较高或更低的云敏感性，从而可以对观察结果进行测试。 进行此类测试需要新的观察结果。该奖项支持的工作收集了水蒸气，雨滴和海水的同位素组成的观察，以检查确定低云特性和敏感性的湿润和干燥过程。 普通水（H2O）由两个氢原子和一个氧原子组成，但是一些水分子含有较重的同位素氘，氧气17和氧气-18的原子。与普通H2O相比，含有较重同位素的水分子更容易凝结，并且比普通的H2O蒸发更慢。 因此，具有相同湿度的空气样品可以根据湿度产生的过程而具有不同浓度的沉重同位素。 例如，如果通过将干燥空气混合在云层上方和海面附近的潮湿空气来设定，则重型同位素的浓度通常高于通过将水凝结在潮湿的低水平空气中来建立相同的湿度水平的情况下。水同位素数据是作为现场活动的一部分收集的，即Eurec4a首字母缩写，以阐明云循环耦合在气候中的作用。 EUREC4A是由德国马克斯·普朗克学院（Max Planck Institute）和法国的Laboratoire de Meteorologie Dynamique领导的跨国运动，其部署为1月20日至2020年2月20日在巴巴多斯举行。该奖项支持了两艘船只，一架飞机和巴巴多斯云式速度的同位素采样。 数据收集和分析与模型模拟以多种方式结合使用。许多工作都涉及模型，这些模型模拟了重型同位素的不同行为，因此可以与同位素数据进行直接比较。研究对基于GCM的不确定性的潜力降低了对未来气候变化的严重性的估计，因此对研究产生了更大的影响。 EUREC4A活动还提供了一个增强国际科学合作的机会，该项目为两名研究生提供了实地经验。 在竞选期间通过博客进行宣传，PIS与新墨西哥州自然历史和科学博物馆合作，通过包括年轻探险家夏季科学训练营和初级演讲计划在内的计划进行宣传。该奖项反映了NSF的法定任务，并通过该基金会的知识优点和广泛的Impactia criperia criperia criperia criperia criperia criperia rection the Anteria the Andior docent of Supporation。