An evaluation of XCTD performance with design improvements

In the last quarter of 1993 Sippican underwent an extensive evaluation of the XCTD/MK12 System. This included a review of the existing system, 7 local tow tests with a reference CTD, 3 sea tests off Bermuda and in-house tests based on regular sampling of the production line. The authors confirmed some of the performance difficulties encountered by users-notably excessive noise and offsets of temperature and/or conductivity at 900 m. Several modifications have been made to improve the overall system performance. Testing of the improved system was done on 18 probes tow tested with the reference CTD and 48 probes dropped off Bermuda. The results showed mean temperature and conductivity accuracy errors of -0.013 ° C and -0.003 mS/cm. The range of accuracy errors was -0.03 to 0.01 °C and -0.03 to 0.02 mS/cm, with standard deviations of 0.012 and 0.013 respectively