Stochastic Dynamics of Sudden Stratospheric Warmings

平流层突然变暖的随机动力学

• 批准号: 1042190
• 负责人: Thomas Birner
• 金额: $ 38.82万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-15 至 2014-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1042190&HistoricalAwards=false
• 关键词: Stochastic; Dynamics; Sudden; Stratospheric; Warmings

Most of the time, the winter circulation of the stratosphere over the Northern Hemisphere polar cap, or the stratospheric polar vortex, is approximately symmetric about the pole, but occasionally it transitions to a dramatically wave-like state, in which stratospheric temperatures rise by as much as 40 Celsius degrees in less than a week. These transitions are termed sudden stratospheric warmings (SSWs), and they constitute the dominant form of variability in the polar stratosphere. This research project will examine the extent to which the stochastic variability of small-scale gravity waves (i.e. buoyancy oscillations) are an important factor in producing SSWs. The work is based on the idea of noise-activated transitions which are known to occur in simple dynamical systems in which two stable equilibrium sates are possible. The research will be conducted with a hierarchy of models of differing complexity, starting from a three-parameter system which is known to have two stable states and progressing to a global atmospheric model with a full three-dimensional representation of the flow in the stratospheric polar vortex.The work will have broader impacts by contributing to the education of a graduate student. Results of the research will contribute to our understanding of SSWs, which have been shown to be consequential for surface weather, and may be of value for improving weather and climate models.

大多数时候，北半球极冠上空的冬季平流层环流，或者说平流层极地涡旋，关于极点大致对称，但偶尔会转变为戏剧性的波状状态，在这种状态下，平流层温度在不到一周的时间内上升多达40摄氏度。 这些转变被称为平流层突然变暖（SSW），它们构成了极地平流层变化的主要形式。 该研究项目将研究小尺度重力波（即浮力振荡）的随机变化在多大程度上是产生SSW的重要因素。 这项工作基于噪声激活转变的思想，已知这种转变发生在简单的动态系统中，其中可能存在两种稳定的平衡状态。 该研究将通过不同复杂度的模型层次进行，从已知具有两个稳定状态的三参数系统开始，逐步发展到具有平流层极涡流动的完整三维表示的全球大气模型。这项工作将通过促进研究生的教育而产生更广泛的影响。 研究结果将有助于我们对SSW的理解，SSW已被证明对地表天气有重要影响，并且可能对改进天气和气候模型有价值。

项目成果

Sudden Stratospheric Warmings and Anomalous Upward Wave Activity Flux

• DOI: 10.2151/sola.13a-002
• 发表时间: 2017-01-01
• 期刊: SOLA
• 影响因子: 1.9
• 作者: Birner, Thomas;Albers, John R.
• 通讯作者: Albers, John R.