A need exists for very low cost temperature and salinity data to be collected from newly designed free-drifting oceanographic platforms. In particular, it is now recognized that a much expanded measurement program for the monitoring of oceanic salinity is required for the analysis and prediction of climate variations. While new autonomous vehicle systems make it feasible to deploy large numbers of monitoring platforms, we sill lack a system for making high quality salinity measurements with long term stability at a sufficiently low cost. The need is particularly acute for a Conductivity/Temperature/Depth (CTD) system capable of being mounted on expendable vehicle systems: examples are the Davis/Webb ALACE Float, RAFOS Floats, surface drifters, and gliding floats under development by groups at Scripps/WHOI/Webb and University of Washington. The high cost and power utilization of currently available commercial CTD systems combined with poor conductivity stability makes them unsuitable for the long term requirements of these new vehicles. Although each of the vehicle systems is unique they all have common CTD requirements: very low cost, low power consumption, high accuracy, long term stability, including immunity from biological fouling, easy low-speed flushing and digital data in a form suited to the expanding system of direct satellite data transmission. Falmouth Scientific Incorporated (FSI) in cooperation with Woods Hole Oceanographic Institution, (WHOI) propose to develop a compact, low cost, CTD system with stability in salinity measurement of better than 0.01 PSU/Year at a cost which is a fraction of existing technologies. The development will build on: 1. recent innovations precision CTD technology by N. Brown 2. integrated temperature and onductivity sensors to minimize lagg correction problems. 3. new low-cost approaches to fabrication and calibration developed through a program of value engineering, and 4. an anti-fouling protection system to assure long term stab.
