Fast EVP Solutions in a High‐Resolution Sea Ice Model

Abstract Sea ice dynamics determine the drift and deformation of sea ice. Nonlinear physics, usually expressed in a viscous‐plastic rheology, makes the sea ice momentum equations notoriously difficult to solve. At increasing sea ice model resolution the nonlinearities become stronger as linear kinem...

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Bibliographic Details
Published in:Journal of Advances in Modeling Earth Systems
Main Authors: Nikolay V. Koldunov, Sergey Danilov, Dmitry Sidorenko, Nils Hutter, Martin Losch, Helge Goessling, Natalja Rakowsky, Patrick Scholz, Dmitry Sein, Qiang Wang, Thomas Jung
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union (AGU) 2019
Subjects:
sea ice dynamics
ice rheology
elastic‐viscous‐plastic
Arctic Ocean
ocean modeling
FESOM
Physical geography
GB3-5030
Oceanography
GC1-1581
Arctic
Sea ice
Online Access:https://doi.org/10.1029/2018MS001485
https://doaj.org/article/0529bb2d905a49fd9686c82635999da5
Description
Summary:Abstract Sea ice dynamics determine the drift and deformation of sea ice. Nonlinear physics, usually expressed in a viscous‐plastic rheology, makes the sea ice momentum equations notoriously difficult to solve. At increasing sea ice model resolution the nonlinearities become stronger as linear kinematic features (leads) appear in the solutions. Even the standard elastic‐viscous‐plastic (EVP) solver for sea ice dynamics, which was introduced for computational efficiency, becomes computationally very expensive, when accurate solutions are required, because the numerical stability requires very short, and hence more, subcycling time steps at high resolution. Simple modifications to the EVP solver have been shown to remove the influence of the number of subcycles on the numerical stability. At low resolution appropriate solutions can be obtained with only partial convergence based on a significantly reduced number of subcycles as long as the numerical procedure is kept stable. This previous result is extended to high resolution where linear kinematic features start to appear. The computational cost can be strongly reduced in Arctic Ocean simulations with a grid spacing of 4.5 km by using modified and adaptive EVP versions because fewer subcycles are required to simulate sea ice fields with the same characteristics as with the standard EVP.

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