Abstract. Tropical precipitation cluster area and intensity distributions follow power laws, but the physical processes responsible for this macroscopic behavior remain unknown.We analyze global simulations at ten-kilometer horizontal resolution that are configured to have drastically varying degrees of realism, ranging from global radiative-convective equilibrium to fully realistic atmospheric simulations, to investigate how dynamics influence precipitation statistics. We find the presence of stirring and large-scale vertical overturning, as associated with substantial planetary and synoptic-scale variability, to be key for having cluster statistics approach power laws. The presence of such large-scale dynamics is reflected in steep vertical velocity spectra. Large-scale rising and sinking modulate the column water vapor and temperature field, leading to a heterogeneous distribution of moist and dry patches and regions of strong mass flux, in which large precipitation clusters form. Our findings suggest that power laws in Earth’s precipitation cluster statistics stem from the robust power laws of atmospheric motions.

中文翻译：

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高分辨率模拟层次上降水集群统计的动态印记


摘要。热带降水集群面积和强度分布遵循幂律，但造成这种宏观行为的物理过程仍然未知。我们以十公里水平分辨率分析全球模拟，这些模拟配置为具有截然不同的真实度，范围从全球辐射到对流平衡到完全真实的大气模拟，以研究动力学如何影响降水统计。我们发现，与行星和天气尺度变化相关的搅拌和大规模垂直翻转的存在，是使星团统计接近幂律的关键。这种大规模动力学的存在反映在陡峭的垂直速度谱中。大规模的上升和下沉调节了柱状水汽和温度场，导致干湿斑块和强质量通量区域的不均匀分布，从而形成大的降水簇。我们的研究结果表明，地球降水集群统计中的幂律源于大气运动的强大幂律。