EGU21-10560
https://doi.org/10.5194/egusphere-egu21-10560
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Modeling a modern-like pCO2 Warm period with two versions of IPSL AOGCM

Ning Tan1, Camille Contoux2, Gilles Ramstein2, Yong Sun3, Christophe Dumas2, Pierre Sepulchre2, and Zhengtang Guo1
Ning Tan et al.
  • 1Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
  • 2Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
  • 3State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics,Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

The mid-Piacenzian warm period (3.264 to 3.025 Ma) is the most recent geological period with present-like atmospheric pCO2. A specific interglacial (Marine Isotope Stage KM5c, MIS KM5c; 3.205 Ma) has been selected for the Pliocene Model Intercomparison Project phase 2 (PlioMIP 2). We carried out a series of experiments according to the design of PlioMIP2 with two versions of IPSL atmosphere–ocean coupled general circulation model (AOGCM): IPSL-CM5A and IPSL-CM5A2. Our results show that the simulated MIS KM5c climate presents enhanced warming at mid- to high latitudes when compared to the PlioMIP 1, resulting from the enhanced Atlantic Meridional Overturning Circulation caused by the high-latitude seaway changes. The sensitivity experiments, conducted with IPSL- CM5A2, show that, apart from the pCO2,  both modified orography and reduced ice sheets contribute substantially to mid- to high latitude warming in MIS KM5c. When considering the pCO2 uncertainties (+/−50 ppmv) during the Pliocene, the response of the modeled mean annual surface air temperature to changes to pCO2 (+/−50 ppmv) is not symmetric, which is likely due to the nonlinear response of the cryosphere (snow cover and sea ice extent).

How to cite: Tan, N., Contoux, C., Ramstein, G., Sun, Y., Dumas, C., Sepulchre, P., and Guo, Z.: Modeling a modern-like pCO2 Warm period with two versions of IPSL AOGCM, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10560, https://doi.org/10.5194/egusphere-egu21-10560, 2021.

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