High Resolution air-sea coupling for downstream storm prediction

风暴路径的结构是中纬度地区天气的关键决定因素之一。它的气候状态取决于高空急流、湍流斜压涡及其相关的热动量涡通量、强迫和耗散过程之间复杂的非线性平衡。在天气和气候模型中，让风暴轨迹的完整结构正确仍然是一个巨大的挑战。主管和合作者最近的工作表明，由于大西洋上空的天气系统，向北的热通量为风暴路径的下游发展和方向提供了强有力的引导。例如，高上游热通量与风暴路径向北倾斜、低空急流在我们经度上向北移动以及反复出现的风暴之间的缩短周期有关。在这一环节中，大多数成分的独立理论支持已经在文献中发表。这项工作得到了NERC项目的支持，并在全球其他几个研究项目的背景下进行，如WGNE-Drag、T-NAWDEX和Primavera。雷丁大学Primavera项目的一些初步工作也表明，非常高分辨率的气候运行如何改善上游热通量特征、风暴路径的倾斜以及下游风暴路径的统计特性。在目前的博士项目中，我们将研究西大西洋地区海洋和大气之间的高分辨率耦合对大气经向热通量的影响以及随之而来的对风暴路径的影响。对于这项工作，我们将与英国环境预测计划的第二阶段联系在一起，该计划旨在为英国开发高分辨率（1公里或更少）的耦合预测模型。该计划的一部分是评估这种高分辨率耦合模型可以解决的新科学。特别是，海洋和大气之间的热交换发生在相对较小的尺度上，这很难解决，但预计它有助于气旋产生的总体热输送，并暗示了预期的风暴路径下游结构。该项目旨在利用高分辨率运行数据，在大范围内建立海洋与大气之间的联系，并建立与下游风暴路径结构的联系。我们将研究统计属性和特定时间段（案例研究）。我们的目标是，这种耦合的高分辨率建模是否能够改进我们对这些大气热通量的预测，以及这种改进的希望是否会导致对英国风暴预报的相应改进。该项目还将利用一种新开发的技术来绘制风暴路径发展的相空间，从而可以以动态一致的方式跟踪上游斜压增长率与风暴路径活动之间的相互作用。

The structure of the storm-track is one of the key determinants of weather in the midlatitudes. Its climatological state depends on a complex non-linear balance between the upper level jet, turbulent baroclinic eddies and their associated eddy fluxes of heat and momentum, and forcing and dissipative processes. Getting the full structure of the storm track right in models is still one of the big challenges of weather and climate models. Recent work by the supervisor and collaborators has shown that northward heat fluxes due to weather systems over the Atlantic provide a strong steer to the downstream development and direction of the storm track. For example, high upstream heat fluxes are associated with a northward tilt of the storm track, a northward shift of the low level jet stream over our longitudes, and reduced periods between recurring storms. Independent theoretical support for most of the ingredients in this link have been published in the literature. This work is supported by a NERC project, and takes place in the context of several other research projects globally, such as WGNE-Drag, T-NAWDEX, and Primavera. Some preliminary work in the Primavera project at the University of Reading has also shown how very high resolution climate runs improve the upstream heat flux characteristics, the tilt of the storm track, and the statistical properties of the downstream storm tracks. In the present PhD project we will be examining the effects of high resolution coupling between the ocean and the atmosphere in the W. Atlantic region on the meridional heat fluxes in the atmosphere and the attendant effects on the storm track. For this work we will tie in with the second phase of UK Environmental Prediction programme, which aims to develop a high resolution (1km or less) coupled prediction model for the UK. Part of this programme is to assess the new science that such high resolution coupled models can address. In particular, heat exchange between the oceans and the atmosphere occurs at relatively small scales which are hard to resolve, but it is expected to contribute to the overall heat transport generated by the cyclone and by implication the expected downstream structure of the storm track. This project aims to use data from high resolution runs to establish the link between the ocean and the atmosphere at a wide range of scales and establish links to the downstream storm-track structure. We will be examining both statistical properties as well as specific time periods (case studies). The aim would be whether high resolution modelling of the coupling can improve our prediction of these atmospheric heat fluxes, and whether the hoped for improvement leads to a concomitant improvement of storm forecasts over the UK. The project will also make use of a newly developed technique to map the phase space of storm track development, where the interaction between upstream baroclinic growth rate and storm track activity can be followed in a dynamically consistent way.