RAFOS Floats in the SYNOP Experiment: 1988-1990

Abstract : RAFOS floats are neutrally buoyant isopycnal drifters which are tracked acoustically by ranging to as many as five sound sources that have been moored at the depth of the permanent sound channel south of the Gulf Stream along a line between 73 deg W and 51 deg W. All sources transmit a precisely timed frequency modulated, continuous wave signal every 8 hrs. The floats, which are equipped with accurate timing, determine the times of arrival of the signals. These are saved in the float's microprocessor memory along with measurements of pressure and temperature. At the end of its mission, each float releases ballast, returns to the surface and starts its radio telemetry. The telemetered data are received by Systeme ARGOS, a French satellite-based data collection and platform location system. Once the data have been assembled the float's trajectory can be reconstructed from the time series of acoustic travel times. Seventy-five RAFOS floats were launched in the center of the Gulf Stream off Cape Hatteras between Apr 1988 and Feb 1990 and Bermuda. Each float was tracked acoustically 30-45 days using sound sources moored to the south of the Gulf Steam at the depth of the permanent sound channel. The main objective was to study the spatial and temporal characteristics of the meandering Gulf Stream east of Cape Hatteras. This document presents all RAFOS float data collected and processed under this program. A plot of the float trajectory for each float is shown, along with a plot of the temperature and pressure time series.