A Simple Model of Gulf Stream Thermal Structure with Application to the Analysis of Moored Measurements in the Presence of Mooring Motion

Abstract

Current mean on long moorings placed in the Gulf Stream near 59°W during 1983?84 experienced time-varying vertical displacements of many hundreds of meters. As an aid to interpreting the resulting velocity and temperature signals, a parametric model of Gulf Stream thermal structure was developed on the basis of a detailed survey of the area. The model translates moored measurements of temperature and pressure to a vertical and cross-stream position in a coordinate system associated with the instantaneous Gulf Stream. Temperature as a function of cross-stream position and pressure, as measured in the survey, is reproduced to within about 0.3°C root-mean-square residual for pressures between 200 and 1500 dbar and temperatures between 4.5° and 19°C using a simple analytical model with a limited number of empirically determined parameters. The model spans a cross-stream range of approximately 150 km. This construct provides a framework for analyzing the measured data and also provides a realistic local representation of the Gulf Stream.