Measurements of turbulence in the zone of strong bottom currents in the strait of Denmark

Abstract

A need for experimental data about the entrain� ment of waters from the Irminger Sea into the jet of cooler and denser waters from the Arctic Basin partic� ipating in the formation of deep waters of the North Atlantic became pressing in relation to the research into climatically important meridional water circula� tion in the North Atlantic within the International EU frame project "Thermohaline Overflow—at Risk?" (THOR) (www.euthor.eu). Turbulence near the interface of the intrusion and surrounding waters plays an important role in the entrainment. However, to the present, there has been little success in direct instru� mental measurements of the microstructure at large depths. The solution of this problem required develop� ment of a freefalling microstructure profiler (MP) that makes possible operative measurements of turbu� lent pulsations of hydrophysical fields at depths up to 3500 m. Such a profiler was made at the Atlantic Branch of the Institute of Oceanology with the support of THOR partners from Hamburg University and the Finnish Meteorological Institute. In this paper we describe a new promising method of microstructure measurements realized during the construction of the profiler and discuss preliminary scientific results of profiler application in the cruise of R/V