The driving force of brine rejection on the deepwater formation in the Hamburg LSG OGCM

Abstract

Ocean general circulation models have become widely disreputed to be useless since they produced a substantial warming of the deep model ocean in standard applications. However, it has been shown recently (Maier-Reimer et al., 1993) that such a warming is not an intrinsic property of the model but may stem from inappropriately chosen boundary conditions. The restoring of the model’s surface values to observations, mostly taken from the Levitus (1982) data set, introduces in high latitudes primarily summer values with the content of meltwater. The thermal boundary values from this data set never falls below the freezing point by more than a few tens of centigrades. With the incorporation of a sea ice model the OGCM can react on prescribed atmospheric temperatures which fall below −30 °C. The problem of a warming deep ocean then vanishes.