Abstract. In this study, we have analyzed extreme daily precipitation during the pre-industrial period from 1501 BCE to 1849 CE in simulations from the Community Earth System Model version 1.2.2. A peak-over-threshold (POT) extreme value analysis is employed to examine characteristics of extreme precipitation and to identify connections of extreme precipitation with the external forcing and with internal modes of variability. The POT analysis shows that extreme precipitation with similar statistical characteristics, i.e., the probability density distributions, tends to spatially cluster. There are differences in the distribution of extreme precipitation between the Pacific and Atlantic sectors, and between the northern-high and southern-low latitudes. Extreme precipitation during the pre-industrial period is largely influenced by the modes of internal variability, such as El Niño-Southern Oscillation (ENSO), the Pacific North American and Pacific South American patterns among others. In general, the modes of variability exhibit significant connection to extreme precipitation in the vicinity to their regions of action. The exception is ENSO which shows more widespread influence on extreme precipitation across the Earth. Effects of the changes in the orbital parameters on extreme precipitation are rather weak compared to those of the modes of internal variability. Still, some regions in central Africa, southern Asia and the tropical Atlantic ocean present statistically significant associations with the changes in the orbital parameters, implying that in these regions, extreme precipitation has increased linearly during the 3351 year pre-industrial period. Tropical volcanic eruptions affect extreme precipitation more clearly on the short term up to a few years. Although, eruptions alter both the intensity and frequency of extreme precipitation, more apparent changes are found in the frequency of extreme precipitation. After eruptions, the return periods of extreme precipitation increase over the extratropical regions and the tropical Pacific, while a decrease is found in other regions. The post-eruption frequency changes of extreme precipitation are associated with ENSO, which itself is influenced by tropical eruptions. Overall, the results show that climate simulations are useful to complement the information on the pre-industrial extreme precipitation, as it can elucidate statistical characteristics and long-term connections of extreme events with natural variability.

中文翻译：

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社区地球系统模型中公元前1501年-公元1849年极端日降水的统计特征

摘要。在这项研究中，我们在社区地球系统模型 1.2.2 版的模拟中分析了从公元前 1501 年到公元 1849 年的前工业化时期的极端日降水量。使用峰值阈值 (POT) 极值分析来检查极端降水的特征，并确定极端降水与外部强迫和内部变异模式的联系。POT 分析表明，具有相似统计特征（即概率密度分布）的极端降水在空间上趋于聚集。太平洋和大西洋地区、北高纬度和南低纬度地区的极端降水分布存在差异。前工业化时期的极端降水主要受内部变率模式的影响，例如厄尔尼诺-南方涛动 (ENSO)、北美太平洋和南美太平洋模式等。一般而言，变异模式与其作用区域附近的极端降水显着相关。例外是 ENSO，它对地球上的极端降水有更广泛的影响。与内部变率模式相比，轨道参数变化对极端降水的影响相当微弱。尽管如此，中非、南亚和热带大西洋的一些地区在统计上与轨道参数的变化存在显着关联，这意味着在这些地区，在前工业化时期的 3351 年期间，极端降水呈线性增加。热带火山喷发在长达几年的短期内更清楚地影响极端降水。虽然火山喷发改变了极端降水的强度和频率，但在极端降水的频率上发现了更明显的变化。火山喷发后，温带地区和热带太平洋极端降水重现期增加，其他地区减少。极端降水的喷发后频率变化与ENSO有关，ENSO本身受热带喷发的影响。总体而言，结果表明气候模拟有助于补充有关工业化前极端降水的信息，