Two modes of appearance of the Odden ice tongue in the Greenland Sea

The Odden ice tongue of the Greenland Sea normally forms locally in winter as frazil-pancake ice allowing for high positive salt fluxes during freezin g that leads to open ocean convection. We report that another type of Odden can develop usually late in the season and is composed of old ice advected through the East Greenland Current and by the Jan Mayen Current. This type causes the introduction of more meltwater that stabilizes the water column , enhances productivity, and affects the carbon cycle in the region. The hi story of Oddens is reviewed and our results indicate that from 1978 through 1997, the first type occurred almost every year except in 1984, 1994, and 1995, while the second type has been observed to occur in 1987 and 1996.