Ventilation der Grönlandsee: Variabilität und ihre Ursachen 1994-2001

Abstract

The noteworthiness of the presented work, which describes the ventilation activity in the Greenland Sea in the late nineties and reevaluates the various ventilation concepts and criteria for itsidentification, is based on the used data set. The data set features qualities, which are only rarely met in oceanography, like comprising more than one or two years, having a consistent spatial and timely resolution as well as a constant high quality of measuring processes and accuracies. Only this allows for an examination of the multi-parametric, through interaction and feedback mechanisms characterised ventilation process in the Greenland Sea by more than a two-point-evaluation. The results emphasize that all concepts based on only one year of observations generalize inadmissibly and are not valid on longer terms. It is also shown that none of the single criteria used as an indicator for convection is generally valid. The analysis of hydrographic data developed during this work leads to a consistent description of the ventilation history in the period of 1994 to 2000 and hence to the needed correction of the ventilation depths. The relevance of the different forcing components is therefore not deduced from specific events with its general validity postulated. Instead, the variety of the occuring ventilation processes could be focused on for the first time. That the necessitated diagnostic instrument for a correct determination of the winterly ventilation is available with this work will be shown for the winter 00/01. If a diagnosis based on hydrographic data is aimed at, the inspection of the density and stability development is necessitated in addition to the temperature and salinity development. Any of the chosen parameters has to be monitored in detail at least once a year on basinscale.