TY - JOUR
T1 - African hydroclimate during the early Eocene from the DeepMIP simulations
AU - Williams, Charles J. R.
AU - Lunt, Daniel J.
AU - Salzmann, Ulrich
AU - Reichgelt, Tammo
AU - Inglis, Gordon N.
AU - Greenwood, David R.
AU - Chan, Wing‐le
AU - Abe‐Ouchi, Ayako
AU - Donnadieu, Yannick
AU - Hutchinson, David K.
AU - Boer, Agatha M.
AU - Ladant, Jean‐baptiste
AU - Morozova, Polina A.
AU - Niezgodzki, Igor
AU - Knorr, Gregor
AU - Steinig, Sebastian
AU - Zhang, Zhongshi
AU - Zhu, Jiang
AU - Huber, Matthew
AU - Otto‐Bliesner, Bette L.
N1 - 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
PY - 2022/5
Y1 - 2022/5
N2 - 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.
AB - 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.
KW - African precipitation
KW - DeepMIP
KW - arly Eocene
KW - paleoclimate
UR - http://www.scopus.com/inward/record.url?scp=85130795324&partnerID=8YFLogxK
U2 - 10.1029/2022PA004419
DO - 10.1029/2022PA004419
M3 - Article
VL - 37
JO - Paleoceanography and Paleoclimatology
JF - Paleoceanography and Paleoclimatology
SN - 2572-4517
IS - 5
M1 - e2022PA004419
ER -