Using Hothouse Climates to Generalize Understanding of Convection, Clouds, and Circulation

对流--上升空气团的湍流运动--是地球大气全球模型中最难捕捉的过程之一。然而，它对我们星球的过去，现在和未来的气候至关重要。由于地球现今的对流发生在一个狭窄的条件范围内，为了深入了解这一现象，迫切需要额外的建模和理论工作，以探索我们目前气候之外的条件。在这个项目中，一个可以直接解决对流和云形成的复杂模型将用于在各种条件下进行调查。该模型的结果将对遥远的过去地球和其他行星的气候条件产生新的见解。重要的是，它们还将被用于“压力测试”现有的对流理论及其对行星气候的影响。这项研究的重点是非常热的大气层（发生在地球遥远的过去），其特点是高湿度。鉴于热带空气在今天的气候中最多只含有百分之几的水蒸气，这个项目将模拟如此温暖的大气，以至于水蒸气成为主要的大气成分。目前尚不清楚云的上升速度、区域覆盖率和大规模环流（如飓风）在这种条件下的表现。这项研究将提供一个新的视角来研究地球历史上奇异时期的对流和气候行为，例如全球雪球冰川事件的后果。这种对我们自己星球的“外星”版本的一瞥是激发好奇心和吸引学生进入地球科学的有力工具。该研究者将利用与哈佛自然历史博物馆的现有关系，向公众传达研究成果，并扩大参观博物馆的不同人群的参与。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Convection – the turbulent motion of ascending air parcels – is one of the hardest processes to capture in global models of Earth’s atmosphere. Yet, it is critically important to our planet’s past, present, and future climate. Because Earth’s present-day convection occurs over a narrow range of conditions, to reach a deep understanding of this phenomenon, there is a strong need for additional modeling and theoretical work that probes conditions beyond our current climate. In this project, a sophisticated model that can resolve convection and cloud formation directly will be used to perform investigations over a wide range of conditions. The model results will yield new insights into climate conditions on Earth in the distant past and on other planets. Importantly, they will also be used to “stress-test” existing theories of convection and its influence on planetary climate. The research focuses on very hot atmospheres (as occurred during Earth’s distant past) that are distinguished by their high humidity. Whereas tropical air in today’s climate contains at most a few percent of water vapor, this project will simulate atmospheres that are so warm that water vapor becomes a major atmospheric constituent. It is currently unknown how cloud updraft speeds, areal coverage, and large-scale circulations such as hurricanes behave under such conditions. The research will offer a new view into the behavior of convection and climate during exotic periods of Earth’s history, such as the aftermath of global Snowball glaciation events. Such glimpses of “alien” versions of our own planet are powerful tools for piquing curiosity and drawing students into geoscience. The investigator will leverage an existing relationship with the Harvard Museum of Natural History to communicate research findings to the public and broaden engagement from the diverse populations that visit the museum.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.