Variability and extremes of poleward breaking Rossby waves over the North Atlantic - European Region (VARNAER)

在热带外大气中，Rossby波对大气环流起着重要的决定作用，特别是在对流层上部和平流层下部。冬季在北大西洋-欧洲地区经常观测到极向破碎Rossby波事件。在这个项目中，我们调查的影响，在对流层上层观测到的背景流向极Rossby波破碎事件和恶劣天气的联系。我们将研究北大西洋-欧洲地区向极破碎Rossby波事件的季节内和年际变化，并诊断每个季节的极端情况下，波浪破碎事件，根据ECMWF再分析（ERA-INTERIM）和分析。通过使用不同的预测数据集，这些事件的可预测性进行了研究。此外，不同的纬向变化的背景流对极Rossby波破碎的预期影响将在简化的全球ECHAM 5模式模拟中进行检查，以提高对这一过程的理解。进一步的关键调查是诊断和中尺度模拟（WRF）的向极Rossby波破碎事件的对流层低层的Grosswetterlage（大尺度流）的变化的影响，以检查不同的作用机制，并了解的影响和影响的次季节差异在北方的恶劣天气。

In the extratropics Rossby waves play an important role in determining the general circulation, especially in the upper troposphere / lower stratosphere region. It is known that events of poleward breaking Rossby waves are often observed over the North Atlantic-European region in wintertime. In this project we investigate the influence of the observed background flow in the upper troposphere on poleward Rossby wave breaking events and the link to severe weather. We will study the intra-seasonal and interannual variability of events of poleward breaking Rossby waves over the North Atlantic-European region and diagnose the extreme cases of the wave breaking events for each season, based on ECMWF Reanalysis (ERA-INTERIM) and analyses. The predictability of such events is investigated by using different forecasts data sets. Furthermore, the expected influence of the different zonally varying background flows on poleward Rossby wave breaking will be examined in simplified global ECHAM5 model simulations in order to improve the understanding of this process. A further key investigation is the diagnosis and mesoscale modelling (WRF) for implications of poleward Rossby wave breaking events on the change of the Grosswetterlage (large scale flow) in the lower troposphere, in order to examine different acting mechanisms, and to understand the sub-seasonal differences of the influence and of the impact on severe weather over Northern Europe.