Quantifying Transport and Mixing in the Stratosphere and Upper Troposphere

量化平流层和对流层上层的传输和混合

• 批准号: 1832842
• 负责人: Gang Chen
• 金额: $ 59.65万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1832842&HistoricalAwards=false
• 关键词: Quantifying; Transport; Mixing; Stratosphere; Upper

This research project will help improve the understanding of the dynamics and predictability of nonlinear processes during a breakdown of polar vortex in the stratosphere, responsible for extreme cold outbreak events in the late winter and early spring. This study may also shed light on processes responsible for transport and mixing across the edge of polar vortex in a changing climate. In the upper troposphere, this is relevant for atmospheric rivers, blocking, and other type of extreme weather that has important societal impacts. The outcome of the research project is expected to have broad implications across a very wide range of fluid flow problems and generate more dialogues between the theory of dynamical systems and applications to atmospheric and oceanic fluids. One graduate student at UCLA will be trained in analysis of observational data and the use of idealized and comprehensive models of the atmosphere. Several undergraduates will be trained in data analysis of atmospheric circulation.The extratropical atmosphere is characterized by the westerly circumpolar flow, with the polar vortex in the stratosphere and the subtropical jet stream in the upper troposphere. Variations in the stratospheric polar vortex and tropospheric jet stream are critical for the dynamics, chemistry, and predictability of these regions. Increases in the amplitude of planetary-scale Rossby waves in the stratosphere interrupt the westerly circumpolar flow, resulting a stronger transport of warm air mass into the polar stratosphere and leading to a sudden warming there. The stronger transport of ozone during a stratospheric sudden warming event helps prevent a continuous loss of ozone over the polar regions during dark winter there. Similarly, the blocked westerly flow in the upper troposphere can impact the transport of energy, momentum as well as water vapor. There is still a lack of understanding about the nonlinear nature of the flow in the presence of large amplitude waves, which limits our ability to predict these events. The objective of this project is to gain new knowledge on the fundamental processes at work for the Lagrangian transport (following the motion of air parcel) in the westerly flow from the dynamical systems point of view in conjunction with the theory of transport and mixing in the atmosphere. More specially, stratospheric warming events will be characterized by the Lagrangian descriptor, a metric stemmed from the dynamical systems, in observations and idealized models of stratosphere-troposphere coupling. The observed patterns will be compared with transport and mixing in a comprehensive chemistry-climate model and chemical compositions in satellite observations at different time scales.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.

该研究项目将有助于提高对平流层极地涡旋崩溃期间非线性过程动力学和可预测性的理解，平流层极地涡旋是造成冬末和早春极端寒冷事件的原因。 这项研究还可能揭示气候变化中负责跨越极涡边缘的传输和混合的过程。 在对流层上层，这与大气河流、阻塞和其他类型的具有重要社会影响的极端天气有关。 该研究项目的成果预计将对广泛的流体流动问题产生广泛影响，并在动力系统理论与大气和海洋流体应用之间产生更多对话。加州大学洛杉矶分校的一名研究生将接受观测数据分析以及理想化综合大气模型的使用培训。 数名本科生将接受大气环流数据分析方面的培训。温带大气的特点是西风环极流，平流层有极地涡旋，对流层上层有副热带急流。 平流层极地涡旋和对流层急流的变化对于这些区域的动力学、化学和可预测性至关重要。 平流层中行星尺度罗斯贝波振幅的增加中断了西风绕极地气流，导致暖气团更强地输送到极地平流层并导致那里突然变暖。在平流层突然变暖事件期间更强的臭氧传输有助于防止极地地区在黑暗的冬季持续损失臭氧。 同样，对流层上层西风气流受阻也会影响能量、动量以及水蒸气的传输。对于存在大幅度波的情况下流动的非线性性质仍然缺乏了解，这限制了我们预测这些事件的能力。 该项目的目标是从动力系统的角度结合输送和混合理论，获得有关西风流中拉格朗日输送（跟随空气团运动）基本过程的新知识。气氛。 更具体地说，平流层变暖事件将通过拉格朗日描述符来表征，拉格朗日描述符是一种源于动力系统的度量，在平流层-对流层耦合的观测和理想化模型中。 观测到的模式将与综合化学气候模型中的传输和混合以及不同时间尺度的卫星观测中的化学成分进行比较。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优势和更广泛的评估进行评估，被认为值得支持。影响审查标准。

项目成果

Constraining the Varied Response of Northern Hemisphere Winter Circulation Waviness to Climate Change

制约北半球冬季环流波动对气候变化的不同响应

• DOI: 10.1029/2022gl102150
• 发表时间: 2023-03
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Nie, Yu;Chen, Gang;Lu, Jian;Zhou, Wenyu;Zhang, Yang
• 通讯作者: Zhang, Yang

Quantifying Eddy Generation and Dissipation in the Jet Response to Upper-versus Lower-level Thermal Forcing

量化射流对上层和下层热强迫的响应中的涡流产生和耗散

• DOI: 10.1175/jas-d-21-0307.1
• 发表时间: 2022-07
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Nie, Yu;Zhang, Yang;Chen, Gang;Yang, Xiu
• 通讯作者: Yang, Xiu

Dependence of Atmospheric Transport Into the Arctic on the Meridional Extent of the Hadley Cell

进入北极的大气输送对哈德来环流圈经向范围的依赖性

• DOI: 10.1029/2020gl090133
• 发表时间: 2020-10
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Yang, Huang;Waugh, Darryn W.;Orbe, Clara;Chen, Gang
• 通讯作者: Chen, Gang

What Controls the Interannual Variability of the Boreal Winter Atmospheric River Activities over the Northern Hemisphere?

是什么控制着北半球冬季大气河活动的年际变化？

• DOI: 10.1175/jcli-d-22-0089.1
• 发表时间: 2022-08
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Ma, Weiming;Chen, Gang
• 通讯作者: Chen, Gang

An Intraseasonal Mode Linking Wintertime Surface Air Temperature over Arctic and Eurasian Continent

连接北极和欧亚大陆冬季地表气温的季节内模式

• DOI: 10.1175/jcli-d-21-0495.1
• 发表时间: 2021-12-13
• 期刊: Journal of Climate
• 影响因子: 4.9