Collaborative Research: Lagrangian Simulations of the Madden Julian Oscillation over Warming Oceans

马登朱利安涛动（MJO）是一个在印度洋上空形成并缓慢向东移动的大型天气系统，直到它在热带太平洋中部附近消散。当它经过一个特定的地点时，通常会导致持续15-30天的雨季，随后是干燥的天气，以及一段时间的强烈西风。伴随MJO的环流在热带大气中遍布全球，它们影响着亚洲、澳大利亚和北美季风降雨开始的时间，以及热带风暴和飓风形成的时间和地点。尽管MJO对全球天气和气候很重要，但几十年来气候模型对它的模拟效果很差，因此目前对其未来变化的预测是不可靠的。参与该项目的科学家们开发了一种新的天气模型，可以更好地预测MJO的行为。它被称为“拉格朗日”，因为它不是在网格点上求解大气运动方程，而是跟踪气团在世界各地的运动。拉格朗日天气模式将用于研究未来随着海洋变暖MJO将如何变化，并更好地理解MJO是如何工作的，因此它的表现也可以在其他模式中得到改进。MJO未来变化的不确定性是气候变化的一个重要未知因素。初步结果表明，随着海洋变暖，MJO将会加强，变得更加频繁，并影响到更广泛的热带地区。潜在的影响包括热带降雨模式的变化，热带风暴和飓风分布的改变，以及有利于更频繁和持续的类似厄尔尼诺现象的海洋变暖的风型变化。该项目还将对两名研究生和几名本科生进行大气环流建模技术和气候动力学方面的培训。

The Madden Julian Oscillation (MJO) is a large weather system that forms over the Indian Ocean and moves slowly eastward until it dissipates near the middle of the tropical Pacific Ocean. When it passes a given location, it typically causes a rainy period that lasts 15-30 days that is followed by dry weather, as well as an extended period of strong westerly winds. The circulations that accompany the MJO go all the way around the world in the tropical atmosphere, and they affect when monsoon rainfall begins in Asia, Australia, and North America, as well as when and where tropical storms and hurricanes form. Despite its importance to global weather and climate, the MJO has been poorly simulated in climate models for decades, so current predictions of how it will change in the future are unreliable. The scientists involved in this project have developed a new kind of weather model that better predicts the behavior of the MJO. It is referred to as "Lagrangian," because instead of solving equations for atmospheric motions on a grid of points, it tracks air masses as they move around the world. The Lagrangian weather model will be used to study how the MJO will change in the future as the oceans warm, and to better understand how the MJO works, so its representation can be improved in other models as well.Uncertainty about future changes to the MJO represent an important X-factor for climate change. Preliminary results suggest that the MJO will intensify, become more frequent, and affect a broader region of the tropics as the oceans warm. Potential impacts include changes to tropical rainfall patterns, altered distributions of tropical storms and hurricanes, and changes in wind patterns that favor more frequent and persistent El Nino-like ocean warming. This project will also educate two graduate students and several undergraduate students about techniques in modeling atmospheric circulations and about climate dynamics.