African Hydroclimate During the Early Eocene From the DeepMIP Simulations

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., Boer, Agatha M., Ladant, Jean‐Baptiste, Morozova, Polina A., Niezgodzki, Igor, Knorr, Gregor, Steinig, Sebastian, Zhang, Zhongshi, Zhu, Jiang, Huber, Matthew and Otto‐Bliesner, Bette L. (2022) African Hydroclimate During the Early Eocene From the DeepMIP Simulations. Paleoceanography and Paleoclimatology, 37 (5). e2022PA004419. ISSN 2572-4517

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Official URL: https://doi.org/10.1029/2022PA004419

Abstract

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.

Item Type: Article
Additional Information: Funding information: UK Natural Environment Research Council. Grant Number: NE/P019137/1 European Research Council. Grant Numbers: FP/2007-868 2013, 40923 JSPS KAKENHI. Grant Number: 17H06104 MEXT KAKENHI. Grant Number: 17H06323 JAMSTEC Swedish Research Council. Grant Numbers: 2016-03912, 2020-04791, 2018-05973. Helmholtz association Alfred Wegener Institute in Bremerhaven National Center for Atmospheric Research National Science Foundation. Grant Numbers: 1852977, OPP 1842059 Natural Sciences and Engineering Council of Canada. Grant Numbers: NE/P01903X/1, 2016-04337 FORMAS. Grant Number: 2018-01621 Australian Research Council. Grant Number: DE220100279 GCRF Royal Society Dorothy Hodgkin Fellowship. Grant Number: DHF\R1\191178
Uncontrolled Keywords: African precipitation, early Eocene, DeepMIP, paleoclimate
Subjects: F800 Physical and Terrestrial Geographical and Environmental Sciences
F900 Others in Physical Sciences
Department: Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User: Rachel Branson
Date Deposited: 17 May 2022 09:26
Last Modified: 17 May 2022 09:30
URI: http://nrl.northumbria.ac.uk/id/eprint/49135

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