The Essential Dynamics of Tropical Rain Belts: Monsoons and Inter-Tropical Convergence Zone (ITCZ) in a Multi-model Ensemble of Idealized Simulations

了解热带地区的海洋和大陆的降雨地点、时间和数量直接关系到生活在那里的人们，也是了解整个全球大气环流的关键信息。这是因为，随着海洋中的水分蒸发，被风吹走，并最终以雨水排出，能量随之通过行星热机移动，影响着各地的气候。该项目旨在阐明热带降雨是如何随着能量进入热带大气的方式的变化而变化的，无论是季节交替的结果，地球轨道的摆动，还是人为的大气成分变化。本研究的目的是探讨海洋雨带和区域季风在其动力学上的基本异同；它的方法是分析用全球大气的计算机模型集合进行的模拟的层次结构，比较在理想模型设置中产生的气候，并确定那些在一系列简化中是稳健的机制。这项研究工作将在两个领域产生重大影响：我们对热带动力学的理解和模型层次的设计。如果我们想要改进我们的模型，提高我们对热带地区和全球未来气候变化的预测，这两个方面的进展都是必要的。这项工作将支持持续和集中的社区领导努力，以促进对季风和海洋雨带动态的创新研究。在这个项目的基础上，集成模拟的设计和协调将通过在国际会议上组织会议和非正式会议来继续进行，在这些会议上，这个大挑战的参与者可以交流结果并计划更多的研究活动。一名博士后科学家，一名研究生和三名本科生将通过该项目接受培训，并从与围绕这些主题聚集的更大社区的互动中受益。从这个项目中获得的知识将被纳入讲座和推广活动，包括拉蒙特开放日和美国自然历史博物馆的成人教育。结果也将通过哥伦比亚大学地球研究所的地球状态博客进行报告。

Knowing where, when, and how much rainfall falls over oceans and continents across the tropics matters directly to the people who live there and is also a key piece of information to understand the atmospheric circulation over the entire globe. This is because -as moisture is evaporated from the ocean, transported by winds, and finally rained out - energy is moved with it across a planetary heat engine that affects climate everywhere. This project aims at elucidating how tropical rainfall changes in response to changes in the way energy enters the tropical atmosphere, be they the results of the alternating of seasons, the wobble of the earth's orbit, or the man-made changes in atmospheric composition. The goal of this research is to address the essential similarities and differences in their dynamics between the oceanic rain belt and the regional monsoons; its approach is to analyze a hierarchy of simulations performed with an ensemble of computer models of the global atmosphere, to compare the climates produced in idealized model setups, and to identify those mechanisms that are robust across a range of simplifications. This research effort will have major impacts in two realms: our understanding of tropical dynamics and our design of model hierarchies. Progress on both fronts is necessary if we want to better our models and improve our prediction of future climate change in the tropics and globally. The effort will support continuous and focused leadership of a community effort to spur innovative research on the dynamics of monsoons and oceanic rain belts. The design and coordination of the ensemble simulations at the base of this project will continue through the organization of sessions and informal meetings at international conferences in which participants to this Grand Challenge can exchange results and plan additional research activities. One post-doctoral scientist, one graduate student and three undergraduates will be trained by this project and benefit from the interactions with the larger community that has gathered around these themes. Knowledge gained from this project will be incorporated in lectures and outreach activities, including the Lamont Open House and adult education at the American Natural History Museum. Results will also be reported via the State of the Planet Blog of the Earth Institute of Columbia University.