Collaborative Research: Revisiting the Low-Frequency Variability of the Extratropical Circulation Using Non-Empirical Orthogonal Function (EOF) Modes and Linear Response Functions

合作研究：使用非经验正交函数 (EOF) 模式和线性响应函数重新审视温带环流的低频变化

基本信息

批准号：
1921413
负责人：
Pedram Hassanzadeh
金额：
$ 38.6万
依托单位：
William Marsh Rice University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-15 至 2023-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1921413&HistoricalAwards=false
关键词：
Collaborative Research Revisiting Low Frequency

项目摘要

One dominant pattern of the atmospheric circulation variability in the extratropical troposphere of both hemispheres is the oscillation between stronger and weaker westerly jet streams with a time scale longer than 10 days. Such low-frequency variability of extratropical westerly jet streams is called the annular mode. The annual mode influences the day-to-day weather and extreme events in the middle and high latitude regions and is therefore of great interest to understand. The annular mode in winter hemisphere also influences, and is influenced by, the stratospheric polar vortex. This project seeks a deeper understanding of the factors that control the annular mode. The outcome of this work will potentially transform the understanding of jet stream variability and weather in the middle and high latitudes. The outcome could also lead to advances in predictability past the current weather prediction barrier of about 10 days, and lead to improvements in capabilities of climate models. Furthermore, the new quantitative framework will aid the interpretation of the range of outcomes predicted by comprehensive climate models. These outcomes have the potential to advance the national and global efforts aimed at preparing for climate change and weather-related extremes, resulting in significant socio-economic benefits. This project will support the education and training of two PhD students and a postdoctoral researcher, thus preparing the next generation of atmospheric dynamists and climate scientists. Some of the tools developed during this work will be used by the PIs in their undergraduate and graduate-level teaching to help the students with visualizing and quantifying some aspects of the jet stream variability. Also, the project will engage K-12 students in climate and computer modeling-related research through several STEM outreach programs at Rice and Stanford.In this project, novel analysis methods will be developed, and will be employed along with computer models and observational data to gain a deeper understanding of this variability of the jet streams. Furthermore, a new framework will be developed to quantitively link this variability in the present day to variability in the future. This framework will integrate the response of the jet stream variability and polar vortex to various climate forcings, such as greenhouse gas increase or ozone depletion. The specific tasks of this project are 1) examining the coupling between the barotropic and baroclinic annular modes in observations and in climate models; 2) developing an eddy feedback model for propagating annular modes; 3) understanding stratospheric influence on the tropospheric annular mode in both hemispheres using numerical experiments; 4) studying low-frequency variability modes and fluctuation-dissipation relationship in climate model simulations to better evaluate the fidelity of the climate change projections in these simulations.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.

两个半球的热带对流层中大气循环变异性的一种主要模式是，较强和较弱的西风喷射流之间的振荡时间超过10天。散热器西风流的这种低频可变性称为环形模式。年度模式会影响中间和高纬度地区的日常天气和极端事件，因此引起了人们的极大兴趣。冬季半球的环形模式也会影响平流层涡流，并受到平流层涡流的影响。该项目寻求对控制环形模式的因素有更深入的了解。这项工作的结果将有可能改变对中间和高纬度的喷气流变异性和天气的理解。结果还可能导致可预测性的进步，超过当前的天气预测障碍约10天，并导致气候模型能力的提高。此外，新的定量框架将有助于解释全面气候模型预测的结果范围。这些结果有可能促进国家和全球努力，旨在为气候变化和与天气有关的极端做准备，从而带来重大的社会经济利益。该项目将支持两名博士学位学生和一名博士后研究人员的教育和培训，从而为下一代大气动力学家和气候科学家做好准备。 PI将在其本科和研究生级教学中使用这项工作中开发的一些工具，以帮助学生可视化和量化喷气流变异性的某些方面。此外，该项目将通过Rice和Stanford的几个STEM外展计划参与K-12学生与与计算机建模有关的研究。在该项目中，将开发新的分析方法，并将与计算机模型和观察数据一起使用，以获得对喷气流的这种可变性的更深入的了解。此外，将开发一个新的框架，以定量将当今的可变性与将来的可变性联系起来。该框架将集成喷气流的变异性和极性涡流对各种气候强迫的响应，例如温室气体增加或臭氧消耗。该项目的具体任务是1）检查在观测和气候模型中，在观测和压力斜角环之间的耦合； 2）开发一个用于传播环形模式的涡流反馈模型； 3）使用数值实验了解两个半球对对流层环形模式的影响； 4）研究气候模型模拟中的低频可变性模式和波动散失关系，以更好地评估这些模拟中气候变化预测的忠诚度。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和更广泛影响的审查标准来通过评估来通过评估来获得支持的。