Collaborative Research: The Quasi-Biennial Oscillation and Madden-Julian Oscillation (QBO-MJO) Connection: Positive Feedbacks from Extratropical Wave Forcing

合作研究：准两年一次振荡和马登-朱利安振荡（QBO-MJO）的联系：温带波强迫的正反馈

• 批准号: 2039384
• 负责人: Lon Hood
• 金额: $ 35.86万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2039384&HistoricalAwards=false
• 关键词: Collaborative; Research; Quasi; Biennial; Oscillation

The Madden-Julian Oscillation (MJO) dominates the tropical climate variability in the troposphere on the 30-to-60-day timescale. During the winter, convective storms associated with the MJO excite planetary-scale wave disturbances that impact the U.S. weather and perturb the stratosphere. The Quasi-Biennial Oscillation (QBO) governs the variability in the tropical lower stratosphere and guides how planetary-scale wave disturbances penetrate into the stratosphere. Observations reveal that the QBO can modulate the occurrence and eastward migration of the MJO pattern. However, this QBO-MJO relationship is not evident in existing global climate models (GCMs). This research seeks to better understand this relationship and address why it remains elusive in models. New insight about the QBO-MJO connection may advance current knowledge of the coupling between the troposphere and stratosphere, extend the forecast range of weather prediction, and guide new GCM improvement. The work will support and train a full-time graduate student and leverage the National Center for Atmospheric Research Whole Atmosphere Community Climate Model (namely, WACCM6-110L), a GCM that simulates realistic MJO and QBO.The research objective is to assess several positive feedback mechanisms that may contribute significantly to the observed QBO influence on the MJO. A key mechanism to assess involves the increased tropical upwelling and destabilization of the tropical upper troposphere/lower stratosphere (UTLS) region during the easterly phase of the QBO (i.e., QBOE) due to the absorption and dissipation of extratropical Rossby waves. These waves are influenced by both the MJO and the QBO. Five tasks are: (1) To quantify the observed differences between QBOE and the westerly phase of the QBO (i.e., QBOW) of the wintertime UTLS temperature and static stability as a function of latitude and longitude; (2) To determine the strength of the MJO-induced extratropical Rossby wave train and resulting upward wave activity flux as a function of MJO strength and QBO phase; (3) To diagnose the strength of the wave train and wave activity flux during the QBOE relative to QBOW; (4) To evaluate if WACCM6-110L can simulate the observed QBO-MJO connection and the observed QBO phase differences in UTLS temperature, subtropical jet structure, and wave activity flux; and (5) To perform new experiments on WACCM6-110L to identify needed model improvements.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.

Madden-Julian振荡（MJO）在30到60天的时间表上主导了对流层的热带气候变化。在冬季，与MJO相关的对流风暴激发了影响美国天气并扰动平流层的行星尺度波动。准双年展振荡（QBO）控制着热带较低平流层的变异性，并指导行星尺度波动如何渗透到平流层中。观察结果表明，QBO可以调节MJO模式的发生和向东迁移。但是，在现有的全球气候模型（GCM）中，这种QBO-MJO关系并不明显。这项研究试图更好地理解这种关系，并解决为什么在模型中仍然难以捉摸。关于QBO-MJO连接的新见解可能会提高对流层和平流层之间耦合的当前知识，扩大天气预测的预测范围，并指导新的GCM改进。这项工作将支持和培训全日制研究生，并利用国家大气研究中心整个大气层社区气候模型（即WACCM6-110L），这是一个模拟现实MJO和QBO的GCM。研究目标是评估几种积极的反馈机制，这些反馈机制可能会对观察到的QBO对MJO产生重大影响。评估的关键机制涉及在QBO（即QBOE）中，热带热带上部对流层/下层平流层（UTLS）区域的热带上升和破坏稳定，这是由于地周期性rossby波的吸收和耗散而导致的。这些波受到MJO和QBO的影响。五个任务是：（1）量化冬季UTLS温度和静态稳定性的QBOE与QBO（即QBOW）之间观察到的差异，这是纬度和经度的函数； （2）确定MJO诱导的诱导的Rossby Wave序列的强度，并导致向上的波活性通量作为MJO强度和QBO相的函数； （3）诊断QBOE期间波列和波动活动通量的强度相对于QBOW； （4）评估WACCM6-110L是否可以模拟观察到的QBO-MJO连接以及观察到的UTLS温度，亚热带射流结构和波活性通量的QBO相差； （5）在WACCM6-110L上进行新的实验以确定所需的模型改进。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估标准通过评估来支持的。

项目成果

QBO/Solar Influences on the Tropical Madden‐Julian Oscillation: A Mechanism Based on Extratropical Wave Forcing in Late Fall and Early Winter

• DOI: 10.1029/2022jd037824
• 发表时间: 2023-03
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: L. Hood;Natasha E. Trencham;Thomas J. Galarneau