Time Evolution of Baroclinic Wave Activity in Stormtracks and Its Relationship with Jetstream Structure

在北半球冬季，大部分天气尺度的风暴活动都是在亚洲和美国东海岸两条相距甚远的中纬度风暴路径上观察到的。有证据表明，波浪(或风暴)活动的变化和风暴路径的位置与它们所在的基本气流的低频变化有关。此外，波浪似乎影响了基本流型的演变。虽然已经收集了许多平均意义上的证据，但仍有必要了解相互作用的时间演变。这项研究的目的是研究天气尺度波和主要风暴路径的时间演变，并将其与基本气流的低频变化联系起来，特别是急流的结构。这项研究使用了30年的数据集。这项研究对提高中长期天气预报水平具有重要意义。如果时间允许，PIS还将研究非洲上空的低层东风急流与所谓的东风或非洲波之间的关系。

In the Northern Hemisphere winter, most of the synoptic scale storm activity is observed in two widely-separated midlatitude stormtracks, along the east coasts of Asia and the United States. There is evidence that the variability in wave (or storm) activity and the position of the stormtrack are related to low frequency variability of the basic flow in which they are embedded. Further, it appears that the waves influence the evolution of the basic flow pattern. While much evidence has been gathered in an averaged sense, there is still a need to understand the time evolution of the interactions. The purpose of this research is to investigate the time evolution of synoptic scale waves and along the major stormtracks and to relate it to low-frequency changes in the basic flow, specifically the structure of the jetstream. The study employs a 30-year data set. This research has important implications for improving medium and long range weather forecasting. If time permits, the PIs will also examine the relationship between the low-level easterly jet over Africa and the so-called easterly or African waves.