Modulation of the seasonal cycle of the Antarctic sea ice extent by sea ice processes and feedbacks with the ocean and the atmosphere

• Published in: The Cryosphere
• Main Authors: H. Goosse, S. Allende Contador, C. M. Bitz, E. Blanchard-Wrigglesworth, C. Eayrs, T. Fichefet, K. Himmich, P.-V. Huot, F. Klein, S. Marchi, F. Massonnet, B. Mezzina, C. Pelletier, L. Roach, M. Vancoppenolle, N. P. M. van Lipzig
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2023
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; Antarctic; Southern Ocean; The Antarctic; Antarc*; Ice Shelf; Sea ice; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-17-407-2023; https://doaj.org/article/26248398388f45f98233c0a2e91375ad

The seasonal cycle of the Antarctic sea ice extent is strongly asymmetric, with a relatively slow increase after the summer minimum followed by a more rapid decrease after the winter maximum. This cycle is intimately linked to the seasonal cycle of the insolation received at the top of the atmosphere, but sea ice processes as well as the exchanges with the atmosphere and ocean may also play a role. To quantify these contributions, a series of idealized sensitivity experiments have been performed with an eddy-permitting ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="f7b7a5d5bfd5c45cef6c295312dc1896"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-17-407-2023-ie00001.svg" width="20pt" height="14pt" src="tc-17-407-2023-ie00001.png"/></svg:svg> ∘ ) NEMO-LIM3 (Nucleus for European Modelling of the Ocean–Louvain-la-Neuve sea ice model version 3) Southern Ocean configuration, including a representation of ice shelf cavities, in which the model was either driven by an atmospheric reanalysis or coupled to the COSMO-CLM 2 regional atmospheric model. In those experiments, sea ice thermodynamics and dynamics as well as the exchanges with the ocean and atmosphere are strongly perturbed. This perturbation is achieved by modifying snow and ice thermal conductivities, the vertical mixing in the ocean top layers, the effect of freshwater uptake and release upon sea ice growth and melt, ice dynamics, and surface albedo. We find that the evolution of sea ice extent during the ice advance season is largely independent of the direct effect of the perturbation and appears thus mainly controlled by initial state in summer and subsequent insolation changes. In ...