MITgcm

Source code: http://mitgcm.org

The oceanic component

The MITgcm is a state-of-the-art ocean general circulation model (OGCM). I use an hydrostatic, implicit free-surface, partial step topography formulation of the MITgcm to simulate the global ocean domain on various continental configurations. A specificity of the MITgcm is the possibility to employ a cubed-sphere grid, which provides a relatively even grid spacing throughout the domain and avoids polar singularities, thus allowing accurate simulation of the polar regions. Interestingly, different grid resolutions are available (Forget et al., 2015), so that it is always possible to find the best compromise between resolution and required computer resources.

The code of the model is still under development, thus benefitting from regular updates.

110Ma_AtlCentral_resolution

Aptian (120 Ma) paleogeography interpolated on cubed-sphere grids of various spatial resolutions. A: CS32 (2.8°, 300 km); B: CS48 (1.9°, 200 km); C: CS96 (1°, 100 km)

The atmospheric component

For my paleoclimate simulations, I use the MITgcm in an ocean-atmosphere coupled setup, adopting the atmospheric component based on the atmospheric GCM of intermediate complexity SPEEDY (Simplified Parametrizations, primitivE-Equation DYnamics, Molteni, 2003).

Marine biogeochemistry

A biogeochemistry model is included, which accounts for oxygen concentration and primary productivity in the ocean.

cs32_pd

Present-day topography / bathymetry interpolated on the MITgcm ‘CS32’ cubed-sphere grid