African Hydroclimate During the Early Eocene From the DeepMIP Simulations.
African Hydroclimate During the Early Eocene From the DeepMIP Simulations.
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DOI：
10.1029/2022pa004419
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发表时间：
2022-05
影响因子：
3.5
通讯作者：
Otto-Bliesner, Bette L.
中科院分区：
文献类型：
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作者：
Williams, Charles J. R.;Lunt, Daniel J.;Salzmann, Ulrich;Reichgelt, Tammo;Inglis, Gordon N.;Greenwood, David R.;Chan, Wing-Le;Abe-Ouchi, Ayako;Donnadieu, Yannick;Hutchinson, David K.;de Boer, Agatha M.;Ladant, Jean-Baptiste;Morozova, Polina A.;Niezgodzki, Igor;Knorr, Gregor;Steinig, Sebastian;Zhang, Zhongshi;Zhu, Jiang;Huber, Matthew;Otto-Bliesner, Bette L.
始新世早期（约 56–48 Myr 前）的特点是二氧化碳估计值较高（1,200–2,500 ppmv）和全球气温升高（比现代高约 10°C–16°C）。然而，始新世早期水文循环的响应受到很大限制，特别是在数据覆盖稀疏的地区（例如非洲）。在这里，我们提出了对始新世早期非洲水文气候的研究，通过深时模型比对项目 (DeepMIP) 中最先进的气候模型集合进行模拟。 DeepMIP 工业化前的模拟与现代观测结果之间的比较表明，模型偏差与模型和地理相关，但是，这些偏差在模型整体平均值中有所减少。始新世模拟与工业化前模拟的比较表明，随着二氧化碳的增加，没有明显的湿润或干燥趋势。结果表明，模型中陆海掩模（相对于现代）的变化可能是模拟的始新世非洲北部降水增加的原因。随着二氧化碳浓度的上升，赤道和西非的降水量增加，北非也随之干燥。还有重要的动力变化，有证据表明，在高二氧化碳浓度下，反气旋低层环流被增加的西南气流所取代。最后，使用古植物学代理数据新编制的定量气候估计进行的模型数据比较表明，与较低二氧化碳水平下的重建稍微更吻合。最先进的气候模型用于研究始新世早期（约 50 密尔前）非洲的水文气候 随着二氧化碳水平的增加，由于低层环流等动态变化，非洲降水量发生变化 模型与新编制的气候估计值之间的比较显示，在较低水平的二氧化碳下，非洲降水量略有更好
The early Eocene (∼56–48 Myr ago) is characterized by high CO2 estimates (1,200–2,500 ppmv) and elevated global temperatures (∼10°C–16°C higher than modern). However, the response of the hydrological cycle during the early Eocene is poorly constrained, especially in regions with sparse data coverage (e.g., Africa). Here, we present a study of African hydroclimate during the early Eocene, as simulated by an ensemble of state‐of‐the‐art climate models in the Deep‐time Model Intercomparison Project (DeepMIP). A comparison between the DeepMIP pre‐industrial simulations and modern observations suggests that model biases are model‐ and geographically dependent, however, these biases are reduced in the model ensemble mean. A comparison between the Eocene simulations and the pre‐industrial suggests that there is no obvious wetting or drying trend as the CO2 increases. The results suggest that changes to the land sea mask (relative to modern) in the models may be responsible for the simulated increases in precipitation to the north of Eocene Africa. There is an increase in precipitation over equatorial and West Africa and associated drying over northern Africa as CO2 rises. There are also important dynamical changes, with evidence that anticyclonic low‐level circulation is replaced by increased south‐westerly flow at high CO2 levels. Lastly, a model‐data comparison using newly compiled quantitative climate estimates from paleobotanical proxy data suggests a marginally better fit with the reconstructions at lower levels of CO2. State‐of‐the‐art climate models are used to study African hydroclimate during the early Eocene (approximately 50 Myr ago) With increasing levels of CO2, there are changes to African precipitation, due to dynamical changes such as low‐level circulation A comparison between the models and newly compiled climate estimates shows a marginally better match at lower levels of CO2