Changes to Madden-Julian Oscillation Winds and Convection in a Future Warmer Climate

马登-朱利安振荡是赤道印度洋和太平洋上空缓慢东移的大尺度热带对流系统的现象。它通过与墨西哥湾、加勒比海和热带大西洋上空的扰动相互作用影响飓风和热带风暴的形成。马登-朱利安振荡还能够在北太平洋和美国上空产生交替的高压和低压模式，导致暴雨事件，干旱，冷空气爆发和其他影响生命和财产的极端天气事件。麦登-朱利安振荡的这种长距离影响为美国极端天气提前几周提供了有用的预报技巧。该项目将探讨在气候变暖的情况下，麦登-朱利安振荡与美国的联系是否可能减弱或发生地理转移，这将对预测和社会产生重大影响。该项目将资助一名研究生和一名博士后研究员。本科生也将通过在科罗拉多州立大学进行的暑期实习计划参与这项研究。该项目将使用一套气候模型模拟来分析麦登-朱利安振荡及其与美国的联系在未来气候变暖时可能会发生的变化。具有降低复杂性的理想化模型将用于识别和理解这些变化的潜在机制。焦点将是热带大气层结的变化，以及急流的位置和强度如何影响马登-朱利安振荡影响中纬度天气的能力。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知识价值和更广泛的影响审查标准进行评估来支持。

The Madden-Julian oscillation is a phenomenon of slowly eastward moving large-scale tropical convection system thousands of miles across over the equatorial Indian Ocean and Pacific. It affects the formation of hurricanes and tropical storms by interacting with disturbances over Gulf of Mexico, Caribbean Sea, and tropical Atlantic Ocean. The Madden-Julian oscillation is also capable of producing alternating high and low pressure patterns over the north Pacific Ocean and the United States, responsible for heavy rainfall events, droughts, cold air outbreaks, and other extreme weather events that affect lives and property. Such long-distance impacts of the Madden-Julian oscillation provide useful forecast skill for extreme weather over the U.S. up to a few weeks in advance. This project will explore if the Madden-Julian oscillation connections to the United States may potentially weaken or shift geographically in a warmer climate, which would have substantial implications for forecasts and for society. This project will support a graduate student and a postdoctoral researcher. Undergraduate students will also be involved in this research through a summer internship program conducted at Colorado State University. This project will use a set of climate model simulations to analyze how the Madden-Julian oscillation and its connections to the United States may change in a future warmer climate. Idealized models with reduced complexity will be used to identify and understand the underlying mechanisms responsible for these changes. Foci will be how changes in the stratification of the tropical atmosphere, and the position and strength of jet streams affect the ability of the Madden-Julian oscillation to impact weather in mid-latitudes. Whether the impacts of El Nino on United States weather may change in a warmer climate will also be examined.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.