A Climatological and Forecast Perspective on the Lower Stratospheric Environment During Synoptic Waveguide Perturbation Events

天气波导扰动事件期间平流层下层环境的气候学和预报视角

• 批准号: 1547814
• 负责人: Andrea Lang
• 金额: $ 36.19万
• 依托单位: SUNY at Albany
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1547814&HistoricalAwards=false
• 关键词: Climatological; Forecast; Perspective; Lower; Stratospheric

The troposphere is the domain of weather systems that affect people and conditions on the ground, while the stratosphere is home to more slowly varying and larger scale circulation features which lie above tropospheric weather. Yet there is increasing awareness that the circulation in the stratosphere can affect tropospheric weather, and a proper representation of the stratosphere is important for numerical models used in medium-range weather forecasting. Likewise, circulation disturbances in the troposphere are known to affect the stratosphere, but the established theory for this influence emphasizes large and slowly moving jet stream meanders known as planetary waves rather than the smaller and faster synoptic waves associated with frontal weather. But recent results suggest that certain kinds of synoptic disturbances can also affect the stratosphere. Research conducted under this award seeks to advance understanding of the mutual interaction between these synoptic disturbances and the stratospheric circulation. Three types of synoptic disturbances are investigated: blocking anticyclones (stationary high pressure systems which induce persistent weather conditions), explosive cyclogenesis (which is associated with severe winter snowstorms along the US eastern seaboard), and the extratropical transition of tropical cyclones (which occurs as hurricanes recurve out of the tropics and interact with the mid-latitude jet streams). All of these disturbances have been shown to have a far-field influence in the downstream direction, through their ability to perturb the waveguide associated with the jet streams. Previous research has also suggested connections to the stratosphere, for instance blocking anticyclones are associated with later sudden stratospheric warmings, and several well-known cases of explosive cyclogenesis (including the 1979 President's Day storm) were preceded by downward wave propagation from the stratosphere. The research will be conducted using objective criteria to identify specific instances of the three types of disturbances, and to subdivide these into cases in which the circumpolar stratospheric circulation is strengthening, strong, weakening, or weak. The analysis will be conducted both using reanalysis datasets and extended-range ensemble forecasts performed as part of the Stratospheric Network for the Assessment of Predictability (SNAP) experiments.The work has broader impacts due to the potential for improvement in weather forecast skill that can come from a better understanding of stratosphere-troposphere interactions accompanying synoptic disturbances that are associated with severe weather. The PI is directly engaged in SNAP, which has been organized to address issues known in the operational medium-range forecast communities. The PI will also create a webpage devoted to real-time diagnostics of stratosphere-troposphere interaction. The webpage will serve as an educational tool for use in real-time forecast discussions in a classroom setting. Beyond these broader impacts, the project supports a full-time PhD student and provide summertime support for an MS student, thereby promoting the next generation of scientists in this research area.

对流层是影响地面上的人和条件的天气系统的领域，而平流层是位于对流层天气之上的变化更慢和更大规模的环流特征的所在地。然而，人们越来越认识到，平流层的环流会影响对流层的天气，适当地表示平流层对于中期天气预报中使用的数值模型很重要。 同样地，对流层的环流扰动也会影响平流层，但关于这种影响的理论强调的是大而缓慢移动的急流，称为行星波，而不是与锋面天气相关的小而快的天气波。 但最近的结果表明，某些天气扰动也可以影响平流层。 在该奖项下进行的研究旨在促进对这些天气扰动与平流层环流之间相互作用的理解。 三种类型的天气扰动进行了研究：阻塞反气旋（静止的高压系统，诱导持续的天气条件），爆发性气旋（这是与严重的冬季暴风雪沿着美国东海岸），和热带气旋的热带外过渡（这是发生在飓风反弯出热带和中纬度急流相互作用）。 所有这些扰动已被证明有一个远场的影响，在下游方向，通过他们的能力，扰动与射流的波导。 以前的研究也表明与平流层的联系，例如阻塞反气旋与后来突然的平流层变暖有关，几个着名的爆炸性气旋形成案例（包括1979年的总统日风暴）之前都有来自平流层的向下波传播。 将使用客观标准进行研究，以确定三种类型扰动的具体实例，并将其细分为环极平流层环流正在加强、加强、减弱或减弱的情况。 分析将使用再分析数据集和作为平流层可预报性评估网络实验一部分的扩展范围集合预报进行，这项工作具有更广泛的影响，因为更好地了解与恶劣天气有关的天气扰动所伴随的平流层-对流层相互作用，有可能提高天气预报技能。 PI直接参与SNAP，其组织目的是解决业务中期预报界已知的问题。 PI还将创建一个专门用于平流层-对流层相互作用实时诊断的网页。 该网页将作为一个教育工具，用于在课堂环境中进行实时预报讨论。除了这些更广泛的影响，该项目还支持全日制博士生，并为MS学生提供夏季支持，从而促进该研究领域的下一代科学家。