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.

平流层是大气层的一层，其中温度随着高度的升高而阻止垂直运动，从而阻止在下面对流层中形成的云，风暴和额叶天气系统。然而，很长的波可以从对流层传播到平流层并影响其循环，最大程度地通过破坏其圆极涡流并引起突然的平流层变暖（SSW）事件。相反，平流层循环可以对对流层天气产生重大影响，尽管这是通过间接途径，而这些途径尚未完全理解。特别是几项研究表明，当平流层极度涡流较弱或被SSW破坏时，冷空气暴发（CAO）的可能性更大，而平流层涡流的状况也会以可能影响表面天气影响的方式影响对流层喷气流。因此，平流层和对流层之间的相互作用具有实际和科学的重要性，并且是实质性研究工作的重点。研究奖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，这些研究强调了空间汇总的量，例如平均涡流的平均强度在极盖上平均，而对流层喷气机的平均速度平均围绕纬度的圆圈进行了平均。半球平均水平足以识别SSW，但它可能会掩盖事件结构的差异，这对于与对流层的相互作用很重要。例如，在半球形平均意义上，平流层涡流可能较弱，因为涡流中心已从极点移开，或者因为涡流实际上已经分为两个不同的涡旋。分裂的涡流和流离失所的涡流可能会以不同的方式影响对流层。它们对喷气流的影响还可能取决于喷气速度的纵向变化，这将被平均纬度圆而掩盖。这项工作主要包括对主要研究人员开发的两个数据集中鉴定出的平流层 - 对流层相互作用的分析。一个称为JetPac，用于用于分析和表征的喷气和对流层泊产品，该产品在包括对流层和下层平流层（包括对流层和下层平流层）上识别了喷气流最大值的位置，并且还识别了每个网格柱中的对流层顶（或多个对流层）。第二个是使用称为Cave-Art的算法开发的，用于使用算法进行区域跟踪来表征和分析涡旋进化。 Cave-Art使用来自计算机视觉的方法来识别平流层涡流的三维结构。 Cave-Art能够在SSW分裂事件时能够跟踪单独的涡旋部分。由于其与CAOS等重大天气事件相关的工作，这项工作具有更大的影响。为该项目生成的数据集提供给研究社区，以最大程度地提高其科学发现的价值。基于Web的外展材料是开发和用于向公众进行宣传的，这些作品支持新墨西哥州理工学院的两名学生。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响评估审查标准，认为值得通过评估值得支持。