Collaborative Research: Evaluating the Roles of Factors Critical to MJO Simulations Using the NCAR CAM3 with Deterministic and Stochastic Convection Parameterization Closures

马登-朱利安振荡（MJO）是一种大规模的降水和大气环流异常模式，它在印度洋上空形成，并向东缓慢传播到赤道中部太平洋。 地球大部分地区都能感受到 MJO 的影响，赤道中部太平洋 MJO 的存在对墨西哥湾的飓风活动产生了强烈的调节作用。 这笔赠款下开展的工作旨在提高 MJO 在全球气候模型 (GCM) 中的代表性，特别是国家大气研究中心社区大气模型 (CAM)。 研究中解决的问题集中于被认为对成功 MJO 模拟至关重要的特定因素： 1) 对流动量传输 [CMT，发生在积云中] 在 MJO 模拟中有多重要？解决这个问题的目的是了解对流动量传输在 MJO 伴随的西风爆发中发挥什么作用。 2) MJO 模拟中对流与层状加热、浅对流与深对流以及随机对流闭合的作用是什么？目标是确定每个过程如何影响 MJO 模拟 [这里层状是指与深积云相关的平坦的上层“砧”]。 3) 这些角色如何依赖于 MJO 开发过程中的 MJO 阶段？ 回答这个问题的目的是了解每个进程在 MJO 演化的不同阶段扮演什么角色。 这项工作的动机来自于使用天气和气候模型模拟和预测 MJO 的困难。由于 MJO 对天气和气候的全球影响，这项工作具有更广泛的影响，因为在模型中更好地表示 MJO 是生成有用的 MJO 预报的第一步。 此外，MJO是气候模型中对流和云过程参数化的重要测试案例，这将增加我们对气候变化预测和预测的信心。 除了这些更广泛的影响之外，该项目还通过本科教学和高中推广活动来促进科学教育。

The Madden-Julian Oscillation (MJO) is a large-scale pattern of precipitation and atmospheric circulation anomalies which forms over the Indian Ocean and propagates slowly eastward towards the central equatorial Pacific Ocean. Impacts of the MJO are felt over much of the earth, and the presence of the MJO in the central equatorial Pacific Ocean exerts a strong modulation of hurricane activity in the Gulf of Mexico. Work conducted under this grant is intended to improve the representation of the MJO in global climate models (GCMs), particularly the National Center for Atmospheric Research Community Atmosphere Model (CAM). The questions addressed in the research focus on specific factors believed to be essential to a successful MJO simulation: 1) How important is convective momentum transport [CMT, occurring in cumulus clouds] in the MJO simulation? The objective of addressing this question is to understand what role convective momentum transport plays in westerly wind bursts accompanying MJOs. 2) What are the roles of convective versus stratiform heating, shallow versus deep convection, and stochastic versus deterministic convection closure in the MJO simulation? The objective is to determine how each of the processes affects the MJO simulation [here stratiform refers to the flat, upper-level "anvils" associated with deep cumulus clouds]. 3) How do these roles depend on the MJO phases in the MJO development process? The objective of answering this question is to understand what role each process plays during different stages of the MJO evolution. Motivation for the work comes from the difficulty in simulating and predicting the MJO using weather and climate models.The work has broader impacts due to the many worldwide impacts of the MJO on weather and climate, as better representation of the MJO in models is a first step in generating useful MJO forecasts. In addition, the MJO is an important test case for the parameterization of convection and cloud processes in climate models, which would increase our confidence in predictions and projections of climate change. Beyond these broader impacts, the project also promotes science education through undergraduate teaching and outreach activities to high schools.