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.

在30-60天的时间尺度上，马登-朱利安振荡（MJO）主导着对流层的热带气候变率。在冬季，与MJO相关的对流风暴激发行星尺度的波扰动，影响美国的天气和扰动平流层。准两年振荡（QBO）控制着热带低平流层的变化，并指导行星尺度波扰动如何渗透到平流层。观测结果表明，QBO对MJO型的发生和东移具有调制作用。然而，这种QBO-MJO关系在现有的全球气候模式（GCMs）中并不明显。这项研究旨在更好地理解这种关系，并解决为什么它在模型中仍然难以捉摸。对QBO-MJO联系的新认识可能会推进对流层和平流层之间耦合的现有知识，扩展天气预报的预报范围，并指导新的GCM改进。这项工作将支持和培训一名全日制研究生，并利用国家大气研究中心的全大气社区气候模式（即WACCM 6 - 110 L），一个GCM，模拟现实的MJO和QBO。研究目标是评估几个积极的反馈机制，可能会显着贡献的QBO对MJO的影响。评估的一个关键机制涉及在QBO的东风阶段（即，QBOE），这是由于对流层外Rossby波的吸收和耗散。这些波受到MJO和QBO的影响。五个任务是：（1）量化QBOE和QBO西风相位之间的观测差异（即，QBOW）冬季UTLS温度和静态稳定度作为纬度和经度的函数;（2）确定MJO诱导的温带Rossby波列的强度以及由此产生的向上波活动通量作为MJO强度和QBO相位的函数;（3）诊断QBOE期间相对于QBOW的波列强度和波活动通量;（4）在UTLS温度、副热带急流结构和波动活动通量等方面，评估WACCM 6 - 110 L能否模拟QBO与MJO的联系以及QBO的位相差;（5）对WACCM 6-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智力价值进行评估来支持和更广泛的影响审查标准。

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