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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.

马登-朱利安涛动 (MJO) 在 30 至 60 天的时间尺度上主导对流层的热带气候变化。在冬季，与 MJO 相关的对流风暴会激发行星规模的波浪扰动，影响美国的天气并扰乱平流层。准两年期振荡（QBO）控制着热带低平流层的变化，并指导行星尺度的波浪扰动如何渗透到平流层。观测表明QBO可以调节MJO图案的发生和东移。然而，这种 QBO-MJO 关系在现有的全球气候模型 (GCM) 中并不明显。这项研究旨在更好地理解这种关系，并解释为什么它在模型中仍然难以捉摸。关于 QBO-MJO 连接的新见解可能会推进当前对对流层和平流层之间耦合的认识，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全大气社区气候模型（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可能对观测到的 QBO 对 MJO 影响做出重大贡献的正反馈机制。评估的一个关键机制涉及 QBO（即 QBOE）东相期间，由于温带罗斯贝波的吸收和消散，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。五项任务是： (1) 量化观察到的 QBOE 和 QBO 西风相（即 QBOW）之间冬季 UTLS 温度和静态稳定性随纬度和经度变化的差异； (2) 确定 MJO 引起的温带罗斯贝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) 评价WACCM6-110L能否模拟观测到的QBO-MJO连接以及观测到的QBO在UTLS温度、副热带急流结构和波浪活动通量方面的相位差； (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 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。