Atmospheric blocking is a key dynamical phenomenon in the mid- and high latitudes, able to drive day-to-day weather changes and meteorological extremes such as heatwaves, droughts and cold waves. Current global circulation models struggle to fully capture observed blocking frequencies, likely because of their coarse horizontal resolution. Here we use convection permitting, nested idealized model simulations for quantifying changes in blocking frequency and Rossby wave breaking compared to a coarser resolution reference. We find an increase in blocking frequency poleward and downstream of the area with increased resolution, while the exact regions depend on the blocking index. These changes are probably due to a more accurate representation of small-scale processes such as diabatic heating, which affect Rossby wave breaking and blocking formation downstream. Our results thus suggest an improved representation of blocking in the next generation of high-resolution global climate models.

中文翻译：

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在超高分辨率理想化气候模型模拟中增强阻塞频率


大气阻塞是中高纬度地区的一个关键动力学现象，能够驱动日常天气变化和极端气象，如热浪、干旱和寒潮。当前的全球环流模型难以完全捕获观察到的阻塞频率，这可能是因为它们的水平分辨率较粗。在这里，我们使用允许对流的嵌套理想化模型模拟来量化与较粗分辨率参考相比阻塞频率和 Rossby 波断裂的变化。我们发现，随着分辨率的提高，区域极地和下游的阻塞频率增加，而确切的区域取决于阻塞指数。这些变化可能是由于更准确地表示了小规模过程，例如非绝热加热，它会影响 Rossby 波的断裂和阻塞下游的形成。因此，我们的结果表明，在下一代高分辨率全球气候模型中，阻塞的表示有所改进。