Session: Glacial Climates (LGM, Last deglaciation, Ice sheet uncertainties, Glacial-interglacial cycles)
Author: Virna Meccia / email@example.com / Max Planck Institute for Meteorology, Hamburg, Germany
Co-author: Uwe Mikolajewicz, Max Planck Institute for Meteorology, Hamburg, Germany;
In most standard Earth System Models (ESMs) the land-sea mask is fixed throughout simulations. However, for long-term simulations with large changes in sea level, topography and ice extents, it is necessary to consider transient ocean boundaries. This is one of the main problems towards simulating a complete glacial cycle with GCM models. We present a tool to allow for an automatic computation of changes in the bathymetry used in the Max Planck Institute Ocean Model (MPIOM). As a first step, the tool remaps a high-resolution topography from ice sheet and glacial isostatic adjustment modelling to the coarse MPIOM grid. In order to avoid isolated domains, our algorithm ensures that ocean areas are connected. Then, it modifies the bathymetry at some key straits to provide for sufficient through-flow depths according to the values found in the high-resolution data. As a second step, the tool adapts MPIOM restart files to changes in bathymetry and land-sea mask. Important aspects are the conservation of mass and tracers. We present the concepts of the algorithms together with first test simulations. Once tested thoroughly the module can be used with MPI-ESM to allow for transient simulations of the last terminations with interactive land-sea mask and bathymetry.