Air-sea Interaction and Island Geography Impacts on Madden-Julian Oscillation (MJO) Initiation and Propagation Through the MAritime Continent

海气相互作用和岛屿地理对马登-朱利安振荡（MJO）在海洋大陆的引发和传播的影响

• 批准号: 1445191
• 负责人: Charlotte Demott
• 金额: $ 51.31万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2020-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1445191&HistoricalAwards=false
• 关键词: Air; sea; Interaction; Island; Geography

Results of this research will benefit the weather forecasting and model development communities, and promote collaboration with other scientists. The project supports one full-time student. Research results will be documented in peer-reviewed publications and shared through participation in national and international workshops and conferences.The Madden-Julian oscillation (MJO) is a large-scale intraseasonal (30-50 day) tropical disturbance with coupled convection and circulation anomalies that propagate eastward at about 5 m/s. The MJO impacts tropical weather across the globe, and influences weather at higher latitudes via teleconnections. The extratropical impacts are especially pronounced when MJO heating is centered over the Maritime Continent and West Pacific. Most state-of-the-art general circulations models (GCMs) struggle to simulate eastward-propagating MJO convection, and those that do typically have difficulty with its propagation across and beyond the Maritime Continent. Coupling an atmosphere-only GCM to an interactive ocean model often improves the magnitude, periodicity, and propagation characteristics of its MJO simulation, but there is no consensus as to why this is true. This research will advance our understanding of the roles of air-sea interaction and Maritime Continent geography on the simulation of the MJO. Expected outcomes of this research are 1) improved understanding of processes critical to MJO initiation and propagation and 2) new insights into why so many GCMs struggle to simulate an eastward propagating MJO capable of translating the Maritime Continent. The objectives of this project are 1) to understand the mechanisms of air-sea interaction on MJO convective development and its impact on moist static energy and 2) to understand the relative influences of air-sea coupling and Maritime Continent geography on MJO propagation. Reanalysis and model output from the super-parameterized Community Atmosphere Model (SPCAM) will be analyzed to assess the mechanisms of air-sea interaction on MJO convective development in coupled and uncoupled simulations, and for MJO events that do and do not propagate across the Maritime Continent. A series of modeling exercises using idealized island geography will be performed to test existing hypotheses concerning the Maritime Continent's impact on MJO convection and its propagation. Analysis methods will be applied to a limited set of coupled climate models to examine the extent to which results are model dependent.

这项研究的结果将使天气预报和模型开发社区受益，并促进与其他科学家的合作。该项目支持一名全日制学生。研究结果将记录在同行评审的出版物中，并通过参加国家和国际研讨会和会议进行分享。马登-朱利安振荡 (MJO) 是一种大规模的季节内（30-50 天）热带扰动，伴有对流和环流异常以大约 5 m/s 的速度向东传播。 MJO 影响全球热带天气，并通过遥连影响高纬度地区的天气。当 MJO 加热集中在海洋大陆和西太平洋时，温带影响尤其明显。大多数最先进的大气环流模型 (GCM) 都难以模拟向东传播的 MJO 对流，而那些模拟的模型通常很难模拟其在海洋大陆上和以外的传播。 将仅大气 GCM 与交互式海洋模型耦合通常可以改善其 MJO 模拟的幅度、周期性和传播特性，但对于为什么会出现这种情况，尚未达成共识。这项研究将加深我们对海气相互作用和海洋大陆地理在 MJO 模拟中的作用的理解。这项研究的预期成果是 1) 提高对 MJO 启动和传播至关重要的过程的理解，2) 对为什么如此多的 GCM 难以模拟能够平移海洋大陆的向东传播 MJO 提供新的见解。该项目的目标是：1）了解海气相互作用对 MJO 对流发展的机制及其对湿静态能量的影响；2）了解海气耦合和海洋大陆地理对 MJO 传播的相对影响。将分析超参数化社区大气模型 (SPCAM) 的再分析和模型输出，以评估耦合和非耦合模拟中 MJO 对流发展的海气相互作用机制，以及在海洋中传播和不传播的 MJO 事件大陆。将使用理想化岛屿地理进行一系列建模练习，以测试有关海洋大陆对 MJO 对流及其传播影响的现有假设。分析方法将应用于一组有限的耦合气候模型，以检查结果在多大程度上依赖于模型。