As the strongest element of the wind-driven circulation in the North Atlantic, the Gulf Stream has been a focus of extensive empirical studies, theoretical debate and modeling simulations. Its characteristics have always been prominent metrics by which the verisimilitude of numerical models has been judged. Despite this attention, there are important characteristics of the Gulf Stream between Cape Hatteras and the Grand Banks that remain poorly known. As a cost-effective means of acquiring more information and insight, the PI's will analyze existing data from the Gulf Stream that either have not been analyzed before or can be analyzed more accurately and completely now. The data in question were collected during the two-year (1988-1990) Synoptic Ocean Prediction (SYNOP) experiment, the most comprehensive experiment ever conducted in the Gulf Stream. While the original SYNOP investigators have completed outstanding studies of the Gulf Stream's kinematics and dynamics with the SYNOP data, there is still a wealth of information locked within that data, because only in the past four years have analysis techniques been developed which can take full advantage of the numerous Inverted Echo Sounder (IES) recorders) or process the moored current and temperature data without the biases arising from inadequate corrections for mooring motion and inaccurate projection into "stream" coordinates. This methodology employs historical hydrographic data in the vicinity of an IES array to construct a temperature function (called the gravest empirical mode, or GEM) with the independent variables depth (actually pressure) and seafloor-to-sea surface acoustic travel time. It will allow independent estimates of GS structure and transport. When the IES-GEM shears are combined with either the HEF transports, or bottom pressure plus near-bottom current meter records, the IES-GEM shears are transformed into absolute velocity profiles. Comparison with earlier analyses will also allow an assessment of the performance of traditional, widely used, analysis techniques. In addition, some important data, from Horizontal Electric Field Recorders, will be analyzed for the first time for its information about the Gulf Stream's structure and variability .
