A quantitative investigation of the relation between deepwater flow and density difference within the thermohaline circulation of a marginal basin for use in lower complexity box models

Abstract

A study of the effect of a number of forcing factors on a marginal basin is conducted using a 3D oceanic circulation model, the Princeton Ocean Model. These factors include relaxation to an air temperature, net evaporation, geometry and the amount of in and outflow within the system. The objective is to further the understanding of how these factors affect the deep-water flux from a marginal basin to a deep basin. Furthermore, it will be attempted to find a quantitative correlation between the deepwater flux and the corresponding density difference between the main and marginal basin. This relation will then be compared to comparable Mediterranean box models. It was found that the implementation of a net evaporation in the system was sufficient to produce a basis for a Mediterranean-like circulation. It was shown that it is necessary to implement both a net evaporation and temperature forcing to produce a realistic Mediterranean-like thermohaline circulation system. Any additional forcing factors only worked to increase or dampen the intensity of the circulation cells. When the variation in density difference between the marginal and deep basin was compared to the deep water flux no conclusive formulation was found based on the current data range. A power law relation was considered the most likely option based on the data present. Finally, it was concluded that a possible underestimation of the deepwater flux exists in comparable Mediterranean box models.