CAREER: The Effect of Latent Heating on the Hadley Circulation

哈德利环流是气候系统的一个主要特征。它的强度和范围与整个热带和亚热带的云、水蒸气、降水、地面风和洋流的分布有关。尽管潜热在驱动哈德利环流中起着主要作用，但大多数先前的理论工作都使用了干燥模式。该项目的研究目标是使用一般环流模型的层次结构来测试Hadley环流的理论，特别关注理想化的潮湿模型，该模型使用简化的参数化，允许大参数变化，易于解释和结果的可重复性。在修正过去的纬向对称理论时，将研究诸如湿气、热量和动量等物理效应的重要性。为了研究这些不同的因素和过程是如何影响哈德利环流的，我们将采用一系列规定的海洋热通量（在赤道周围对称，在赤道外中心对称）、纬向不对称边界条件、对流层顶高度的变化以及对流参数化的变化进行模拟。还将用理想的海洋-大气耦合模式进行模拟。模型的层次选择是先在最简单的模型中分离出单个物理效应，然后系统地加入不同的效应，再与更全面的模型进行比较。这个项目的教育目标是让高中生、本科生和公众了解大气中凝结作为热源的重要性。在高中阶段，这将通过来自两个不同气候带的学生进行一系列的实验室实验来完成。学生们将测量冷却饮料罐外部的冷凝对提高其中液体温度的影响，并将比较两个地点的数据。首席研究员（PI）将访问华盛顿州中部的地点，那里有很高比例的少数民族和低收入学生，并就冷凝对大气的影响发表演讲。除了外展实验外，教育和研究目标将通过在项目中使用本科生和研究生的研究助理以及以论文的形式向公众展示研究成果和概念来整合。

The Hadley circulation is a dominant feature of the climate system. Its strength and extent are connected to the distribution of clouds, water vapor, precipitation, surface winds, and ocean currents throughout the tropics and subtropics. Despite the primary role of latent heating in driving the Hadley circulation, most previous theoretical work has used dry models. The research goals of this project are to test theories for the Hadley circulation using a hierarchy of general circulation models, with particular focus on an idealized moist model that uses simplified parameterizations and allows for large parameter variations and ease of interpretation and reproducibility of results. The importance of physical effects, such as eddy fluxes of moisture, heat, and momentum in modifying the zonally symmetric theories in the past will be investigated. Simulations with a range of prescribed ocean heat fluxes (both symmetric about the equator and centered off-equator), with zonally asymmetric boundary conditions, with changes to the height of the tropopause, and with changes to the convective parameterization will be performed in order to investigate how these different factors and processes affect the Hadley circulation. Simulations with an idealized coupled ocean-atmosphere model will also be performed. The hierarchy of models is chosen to isolate individual physical effects in models of maximal simplicity first, then add in different effects systematically, and then compare with more comprehensive models.The educational goals of this project are to inform high school students, undergraduates, and the general public about the importance of condensation as a source of heat in the atmosphere. At the high-school level, this will be accomplished with a series of laboratory experiments with students from two different climate zones. The students will measure the effect of condensation on the outside of cooled drink cans on raising the temperature of the liquid therein, and will compare data between the two sites. The Principal Investigator (PI) will visit the site in central Washington State, which has a high percentage of minority and low-income students, to give presentations about the effects of condensation on the atmosphere. In addition to the outreach experiments, educational and research goals will be integrated by using undergraduate and graduate research assistants in the project and by presenting research results and concepts to the general public in the form of essays.