Dynamics and Predictability of Extratropical Vortices

温带涡旋的动力学和可预测性

• 批准号: 0552004
• 负责人: Gregory Hakim
• 金额: $ 27.78万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0552004&HistoricalAwards=false
• 关键词: Dynamics; Predictability; Extratropical; Vortices

Tropopause vortices are ubiquitous features at high latitudes. While some of these vortices, such as cut-off cyclones, are related to extratropical cyclogenesis and Rossby wave breaking, others appear to occur independently of these processes. In particular, over the arctic, vortices occur poleward of the extratropical jet streams and are a defining characteristic of the interior of the larger circumpolar vortex. Explanations for arctic vortex origination and intensification are lacking, and these issues form the basis for the research. A second thrust of the research concerns the predictability of the larger-scale flows that contain these vortices. Key hypotheses regarding vortex intensity changes will be tested using both observational and modeling approaches and these are: (1) radiative cooling is responsible for saturating the core of arctic vortices, and that this process is important for the vortex dynamics; (2) weaker stability near the tropopause may allow the level of maximum latent heating associated with condensation to move up closer to the dynamical tropopause; and (3) radiation may dominate latent heating for very cold vortices, and latent heating may dominate for warmer vortices. Modeling strategy will be applied to systematically test the hypotheses regarding the feedbacks of radiation and latent heating on tropopause vortex dynamics. Intellectual Merit: The PI will (1) test key hypotheses regarding vortex intensity changes using both observational and modeling approaches; (2) use observational work to determine the large-scale patterns associated with vortex intensity changes for a large sample of cases; and (3) will examine individual cases using numerical model simulations and ensemble-based state estimation techniques. Broader Impacts: The research will improve our understanding of the polar vortices and also increases the predictability of mid-latitude weather. A graduate and undergraduate student will be trained in the observational and modeling analysis of polar vortices.

在高纬度上，Tropopause涡旋是无处不在的特征。尽管这些涡流中的一些，例如截止旋风，与驱动的环旋转病和rossby波的破裂有关，但其他涡流似乎与这些过程无关。特别是，在北极上，涡流出现在热带喷射流的极点，并且是较大圆极涡流内部的定义特征。缺乏对北极涡流起源和强化的解释，这些问题构成了研究的基础。该研究的第二个动力涉及包含这些涡旋的大规模流的可预测性。有关涡旋强度变化的关键假设将使用观察和建模方法进行测试，这些假设是：（1）辐射冷却是为了使北极涡旋的核心饱和，并且此过程对于涡流动力学很重要； （2）较弱的对流层顶可能允许与凝结相关的最大潜在加热水平，从而更靠近动力学对流层顶； （3）辐射可能会在非常冷的涡旋中占主导地位，而潜在加热可能会占主导地位。建模策略将用于系统地测试有关对流层顶涡流动力学上辐射和潜在加热反馈的假设。智力优点：PI将使用观察和建模方法来检验有关涡旋强度变化的关键假设； （2）使用观察工作来确定大量病例样本的与涡旋强度变化相关的大规模模式； （3）将使用数值模型模拟和基于整体的状态估计技术检查单个案例。更广泛的影响：这项研究将提高我们对极地涡度的理解，并提高中纬度天气的可预测性。研究生和本科生将接受对极性涡流的观察和建模分析的培训。