Precipitation is changing as the climate warms, and downpours can become more intense due to the increased water holding capacity of the atmosphere. However, the exact nature of the precipitation response and its characteristics is still not well understood due to the complex nature of the physical processes underlying the formation of clouds and precipitation. In this study, present and future Norwegian climate is simulated at convection-permitting scales with a regional climate model. The future climate is a high emission scenario at the middle of the century. Hourly precipitation is separated into three categories (convective, stratiform, and orographically enhanced stratiform) using a physically-based algorithm. We investigate changes in the frequency, intensity and duration of precipitation events for each category, delivering a more nuanced insight into the precipitation response to a changing climate. Results show very strong seasonality, with significant intensification of autumn precipitation. An increase in convective precipitation frequency and intensity dominates the climate change signal regardless of season. While changes in winter and summer are well explained by thermodynamical theory, the precipitation response in autumn and spring deviates from the idealised thermodynamic response, partly owing to changes in cloud microphysics. These results show that changes in the precipitation distribution are affected in complex ways by the local climatology, terrain, seasonality and cloud processes. They illustrate the need for further and more detailed investigations about physical processes underlying projected precipitation changes and their seasonal and regional dependence.

随着气候变暖，降水正在发生变化，由于大气持水能力的增加，倾盆大雨会变得更加强烈。然而，由于云和降水形成背后的物理过程的复杂性，降水响应的确切性质及其特征仍未得到很好的理解。在这项研究中，使用区域气候模型在允许对流的尺度上模拟当前和未来的挪威气候。未来气候是本世纪中叶的高排放情景。使用基于物理的算法将每小时降水分为三类（对流、层状和地形增强层状）。我们调查了每个类别降水事件的频率、强度和持续时间的变化，对降水对气候变化的反应提供更细致入微的见解。结果显示季节性很强，秋季降水明显增强。无论季节如何，对流降水频率和强度的增加都主导着气候变化信号。虽然热力学理论很好地解释了冬季和夏季的变化，但秋季和春季的降水响应偏离了理想化的热力学响应，部分原因是云微物理的变化。这些结果表明，当地气候、地形、季节性和云过程以复杂的方式影响着降水分布的变化。