权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Winds and the Weather: Evaluating Three Dimensional (3D) Stratospheric / Tropospheric Jet Relationships and Their Roles in Extreme Cool-Season Weather Events

风和天气：评估三维 (3D) 平流层/对流层急流关系及其在极端冷季天气事件中的作用

基本信息

批准号：
2015906
负责人：
Gloria Manney
金额：
$ 50.95万
依托单位：
NorthWest Research Associates, Incorporated
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：
2020-07-15 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2015906&HistoricalAwards=false
关键词：
Winds Weather Evaluating Three Dimensional

项目摘要

The stratosphere is a layer of the atmosphere where the increase of temperature with height discourages vertical motions, thereby barring entry to the clouds, storms, and frontal weather systems that form in the troposphere below. Nevertheless very long waves can propagate from the troposphere into the stratosphere and influence its circulation, most dramatically by disrupting its circumpolar vortex and causing a sudden stratospheric warming (SSW) event. Conversely, the stratospheric circulation can have a substantial effect on tropospheric weather, albeit through indirect pathways which are not entirely understood. In particular several studies have shown that cold air outbreaks (CAOs) are more likely when the stratospheric circumpolar vortex is weak, or disrupted by an SSW, and the condition of the stratospheric vortex can also influence the tropospheric jet streams in ways that can in turn affect surface weather. Interactions between the stratosphere and troposphere are thus of practical as well as scientific importance and are a focus of substantial research effort.Research under this award uses novel methods to characterize the three-dimensional structure of stratosphere-troposphere interactions. The work complements previous studies which have emphasized spatially aggregated quantities like the mean strength of the stratospheric vortex averaged over the polar cap and the mean speed of tropospheric jets averaged around circles of latitude. A hemispheric average can suffice to identify an SSW but it may conceal differences in the structure of the event which matter for its interactions with the troposphere. For instance the stratospheric vortex can be weaker in a hemispherically-averaged sense because the vortex center has moved away from the pole, or because the vortex has in fact split into two distinct vortices. A split vortex and a displaced vortex are likely to influence the troposphere in different ways. Their influence on jet streams may also depend on longitudinal variations in jet speed that would be obscured by averaging around a latitude circle.The work consists primarily of analysis of stratosphere-troposphere interactions identified in two datasets developed by the Principal Investigators. One is called JETPAC, for JEt and Tropopause Products for Analysis and Characterization, which identifies the locations of jet stream maxima on a three-dimensional grid including the troposphere and lower stratosphere and also identifies the tropopause (or multiple tropopauses) in each grid column. The second is developed using an algorithm called CAVE-ART, for Characterization and Analysis of Vortex Evolution using Algorithms for Region Tracking. CAVE-ART uses methods from computer vision to identify the three-dimensional structure of the stratospheric polar vortex. CAVE-ART is able to track separate pieces of the vortex in the event of a splitting SSW event.The work has broader impact due its relevance to significant weather events such as CAOs. The datasets generated for the project are made available to the research community in order to maximize their value for scientific discovery. Web-based outreach materials are developed and used to conduct outreach to the public, and the work supports two students at New Mexico Tech.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.

平流层是大气层中的一层，其中温度随着高度的增加而阻碍垂直运动，从而阻止了下面对流层中形成的云层、风暴和锋面天气系统的进入。然而，很长的波可以从对流层传播到平流层并影响其环流，最显着的方式是破坏其绕极涡并引起突然的平流层变暖（SSW）事件。相反，平流层环流可以对对流层天气产生重大影响，尽管是通过尚未完全了解的间接途径。特别是一些研究表明，当平流层环极涡较弱或受到SSW干扰时，冷空气爆发（CAO）的可能性更大，而且平流层涡旋的状况也会影响对流层急流，进而影响地表天气。因此，平流层与对流层之间的相互作用具有实用性和科学重要性，并且是大量研究工作的重点。该奖项的研究使用新颖的方法来表征平流层-对流层相互作用的三维结构。这项工作补充了以前的研究，这些研究强调空间聚合量，例如极冠上平均平流层涡旋的平均强度和围绕纬度圈平均的对流层急流的平均速度。半球平均值足以识别SSW，但它可能掩盖了事件结构的差异，而这对其与对流层的相互作用很重要。例如，平流层涡旋在半球平均意义上可能较弱，因为涡旋中心已远离极点，或者因为涡旋实际上已分裂成两个不同的涡旋。分裂涡旋和移位涡旋可能以不同的方式影响对流层。它们对急流的影响也可能取决于急流速度的纵向变化，而这种变化会被围绕纬度圈的平均所掩盖。这项工作主要包括对主要研究人员开发的两个数据集中确定的平流层-对流层相互作用的分析。其中一种称为 JETPAC，即用于分析和表征的 JEt 和对流层顶产品，它可以识别包括对流层和平流层下层在内的三维网格上急流最大值的位置，还可以识别每个网格列中的对流层顶（或多个对流层顶）。第二个是使用称为 CAVE-ART 的算法开发的，用于使用区域跟踪算法对涡演化进行表征和分析。 CAVE-ART 使用计算机视觉方法来识别平流层极涡的三维结构。 CAVE-ART 能够在 SSW 分裂事件中跟踪涡旋的各个部分。由于与 CAO 等重大天气事件相关，这项工作具有更广泛的影响。为该项目生成的数据集可供研究界使用，以最大限度地发挥其科学发现的价值。基于网络的宣传材料被开发出来并用于向公众进行宣传，这项工作支持了新墨西哥理工学院的两名学生。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。