Rossby Wave Packets in a Changing Climate and Implications for Weather Extremes in Europe

随着大气中温室气体浓度的增加，气候模式预测对全球热力学反应的看法一致，例如平均地表温度上升或水蒸气增加。然而，变暖的分布并不均匀，这导致在全球和区域尺度上的大气环流的响应很大的不确定性。这些不确定性使人们无法对特定地区极端天气的未来特征做出强有力的陈述。拟议的工作将适用于最近开发的诊断Rossby波包的多成员气候模式集合，以调查其特征属性的变化，并将这些变化与内部气候变率区分开来。这些诊断的关键新奇在于它们在空间和时间上是局部的，因此非常适合探索Rossby波包与旋风和块等较小尺度流动特征之间的相互作用。此外，该项目将定义和调查一个真正独立于波浪的无涡背景状态，有助于将波浪特性的趋势与纬向平均流的趋势分开。最后，这些分析将用于研究大气环流的变化如何影响特定区域，特别是欧洲的极端温度和降水。

As the concentration of greenhouse gases in the atmosphere increases, climate model projections agree on global thermodynamic responses such as the rise of the mean surface temperature or the increase in water vapor. However, the warming is not distributed uniformly, which induces large uncertainties in the response of the atmospheric circulation at both the global and the regional scale. These uncertainties prevent one from making robust statements about the future characteristics of weather extremes in specific regions. The proposed work will apply recently developed diagnostics for Rossby wave packets to a multi-member climate model ensemble in order to investigate changes in their characteristic properties and distinguish these changes from internal climate variability. The key novelty of these diagnostics is that they are local in space and time and, therefore, well suited to explore the interplay between Rossby wave packets and smaller-scale flow features like cyclones and blocks. In addition, the project will define and investigate an eddy-free background state that is truly independent of the waves, helping to disentangle trends in wave properties from trends in the zonal mean flow. Finally, these analyses will be used in order to investigate how changes in atmospheric circulation affect temperature and precipitation extremes in specific regions and, especially, in Europe.