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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

基本信息

批准号：
2039388
负责人：
Thomas Galarneau
金额：
$ 12.22万
依托单位：
University of Oklahoma Norman Campus
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=2039388&HistoricalAwards=false
关键词：
Collaborative Research Quasi Biennial Oscillation

项目摘要

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，麦登-朱利安涛动（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了行星尺度的波扰动，影响了美国的天气并扰乱了平流层。准两年一次振荡（QBO）控制着热带平流层低层的变率，并指导行星尺度波扰动如何穿透平流层。观测结果表明，QBO对MJO型的发生和东移具有调节作用。然而，这种QBO-MJO关系在现有的全球气候模式（GCMs）中并不明显。本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连接的新认识，将有助于推进当前对流层与平流层耦合的认识，扩大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群落气候模式（即WACCM6-110L），这是一个模拟现实MJO和QBO的GCM。本研究的目的是评估可能对观察到的QBO对MJO的影响有显著贡献的几种正反馈机制。一个关键的评估机制涉及在QBO（即QBOE）的东风阶段，由于热带罗斯比波的吸收和消散，热带对流层上层/平流层下层（UTLS）区域的热带上升流增加和不稳定。这些波同时受到MJO和QBO的影响。五个方面的工作是：(1)量化观测到的QBOE与QBO西风相（即QBOW）冬季UTLS温度和静态稳定性的差值随经纬度的变化；(2)确定MJO诱发的温带Rossby波列强度及其上行波活动通量与MJO强度和QBO相位的关系；(3)诊断QBOE期间相对于QBOW的波列强度和波活动通量；(4)评价WACCM6-110L能否模拟观测到的QBO- mjo连接和观测到的QBO相位差在UTLS温度、副热带急流结构和波活动通量方面的变化；(5)在WACCM6-110L上进行新的实验，确定需要改进的模型。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。