Recently, much attention has been devoted to better understand the internal modes of variability of the climate system. This is particularly important in mid-latitude regions like the North-Atlantic, which is characterized by a large natural variability and is intrinsically difficult to predict. A suitable framework for studying the modes of variability of the atmospheric circulation is to look for recurrent patterns, commonly referred to as Weather Regimes. Each regime is characterized by a specific large-scale atmospheric circulation pattern, thus influencing regional weather and extremes over Europe. The focus of the present paper is the study of the Euro-Atlantic wintertime Weather Regimes in the climate models participating to the PRIMAVERA project. We analyse here the set of coupled historical simulations (hist-1950), which have been performed both at standard and increased resolution, following the HighresMIP protocol. The models’ performance in reproducing the observed Weather Regimes is assessed in terms of different metrics, focussing on systematic biases and on the impact of resolution. We also analyse the connection of the Weather Regimes with the Jet Stream latitude and blocking frequency over the North-Atlantic sector. We find that—for most models—the regime patterns are better represented in the higher resolution version, for all regimes but the NAO-. On the other side, no clear impact of resolution is seen on the regime frequency of occurrence and persistence. Also, for most models, the regimes tend to be more tightly clustered in the increased resolution simulations, more closely resembling the observed ones. However, the horizontal resolution is not the only factor determining the model performance, and we find some evidence that biases in the SSTs and mean geopotential field might also play a role.

最近，人们已经投入大量精力来更好地了解气候系统内部变化的模式。这在北大西洋等中纬度地区尤为重要，该地区的自然变异性很大，本质上难以预测。研究大气环流变化模式的合适框架是寻找通常被称为天气制度的周期性模式。每个政权都有一个特定的大规模大气环流特征，从而影响区域天气和整个欧洲的极端情况。本文的重点是在参与PRIMAVERA项目的气候模型中研究欧洲大西洋冬季天气制度。我们在这里分析了一组耦合的历史模拟（hist-1950），遵循HighresMIP协议以标准分辨率和更高的分辨率执行了这些操作。该模型在再现观测到的天气状况方面的性能是根据不同的指标进行评估的，重点是系统偏差和分辨率的影响。我们还分析了北大西洋地区射流纬度和阻塞频率与天气状况的联系。我们发现，对于大多数模型而言，除NAO-以外的所有体制，在高分辨率版本中都可以更好地表示体制模式。另一方面，没有看到解决方案对政权的发生和持久性发生明显影响。同样，对于大多数模型，在增加分辨率的模拟中，这些状态往往更紧密地聚集在一起，与观察到的情况更相似。然而，