Session: Glacial Climates (LGM, Last deglaciation, Ice sheet uncertainties, Glacial-interglacial cycles)
Author: Anna Matulka / firstname.lastname@example.org / MARUM
Co-author: Andre Paul, MARUM;
Matthias Prange, MARUM;
The land-sea mask in Earth-system models is usually fixed. However, in the case of large changes in sea level, time-dependent ocean boundaries and bottom topography need to be considered (e.g. for simulations of the last deglaciation through which the global sea level increased by about 120 m). The aim of this project is to make the ocean component POP (Parallel Ocean Program) of the CESM (Community Earth System Model) capable of dealing automatically with those changes. A suitable algorithm was developed and tested. Manual checks were performed regarding the control of key straits, modification of through-flow depths at important sills, connection of ocean basins and determination of closed basins (where necessary, isolated points were removed). The algorithm applies changes in the land-sea mask whenever sea level change crosses a z-level of the vertical grid. The land-sea changes take place upon a restart of the model, which requires a modification of restart files. New ocean cells are initialized with nearest-neighbour values.