Understanding the drivers of precipitation and their changes in a non-stationary climate is crucial for effective climate adaptation and water resource management, as it helps us anticipate and respond to shifting precipitation patterns and their impacts. Here, analysing simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) we show that the conditional probability of extreme daily precipitation given joint extremes of two drivers (precipitable water and vertical velocity) will be stable in a 3 °C warmer future. Consistent with earlier work, we find that the near-global increase in precipitable water (thermodynamic influence) is the baseline for changes in extreme precipitation, which are modulated by changes in vertical velocity (dynamic influence). Thus, in regions where vertical velocity increases, the effect of the two drivers is additive and their changes contribute to an increase in extreme precipitation. The changes of the two drivers are opposite where vertical velocity decreases, resulting in only small increases in extreme precipitation or even a decrease. Furthermore, we reveal that there are moderate changes in the dependence between the drivers, which are larger over the ocean than over landmasses, but they contribute only little to the overall changes in extreme precipitation. We conclude that the use of two very simple drivers that are readily available from climate models can be of great utility for evaluating precipitation extremes in models and understanding their projected changes.

中文翻译：

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CMIP6 模型中与可降水量和垂直速度变化相关的极端日降水量的预测变化

了解非平稳气候下降水的驱动因素及其变化对于有效的气候适应和水资源管理至关重要，因为它有助于我们预测和应对不断变化的降水模式及其影响。在此，通过分析耦合模型比对项目第 6 阶段 (CMIP6) 的模拟，我们表明，在两个驱动因素（可降水量和垂直速度）的联合极端情况下，极端日降水的条件概率将在未来变暖 3 °C 的情况下保持稳定。与早期的工作一致，我们发现可降水量的近全球增加（热力学影响）是极端降水变化的基线，而极端降水变化受到垂直速度变化（动态影响）的调节。因此，在垂直速度增加的地区，两个驱动因素的影响是相加的，它们的变化导致极端降水的增加。两个驱动因素的变化相反，垂直速度减小，导致极端降水仅小幅增加甚至减少。此外，我们发现驱动因素之间的依赖性存在适度的变化，海洋上的依赖性大于陆地上的依赖性，但它们对极端降水的总体变化的贡献很小。我们的结论是，使用气候模型中容易获得的两个非常简单的驱动因素对于评估模型中的极端降水量并了解其预计变化非常有用。