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46 st / February 2016 www.sea-technology.com over part of the sensor electrode com- ponents, the sensor recalibrated within 0.001 S/m (±0.005 psu) with a simple fushing with hot water. Recovered Argo Float CTDs Sea-Bird had the invaluable oppor- tunity to post-calibrate six Argo CTDs from foats that had been recovered through various means (e.g., by fsher- men, beachcombers, research vessels). The foats spent anywhere from one to three-and-a-half years at sea, with up to six years between initial calibra- tion and post-recovery calibration. The CTDs were calibrated in as-received condition, prior to cleaning or main- tenance. Conductivity sensor post-cal- ibrations showed sensor drift less than 0.001 S/m for all but one of the Argo CTDs. The residual conductivity differ- ence was calculated from the differ- ence between the CTD sensor reading using the deployment calibrations and the known calibration bath conductivi- ties during post-calibration. Excluding results from SN 0933, the recovered CTDs showed residual conductivity differences expressed as salinity of < 0.0025 psu for all sensors deployed for one or more years. The residual tem- perature differences indicate the differ- ence between the CTD sensor reading based on deployment calibrations and the known calibration bath tempera- tures during post-calibration. All recov- ered CTDs showed temperature differ- ences of < 0.002° C over the length of their deployment. Further demonstrat- ing the stability of foat CTDs, four of six temperature sensors were recali- brated within 0.001° C of their original production calibration, consistent with recalibrations of similar sensors held in the laboratory. Implications for Argo Repeated calibration of several Argo CTDs over fve years in the Sea-Bird Argo foat facility indicate a very stable calibration system and low-drift perfor- mance of the SBE 41 and 41cp designs. In addition, results from six Sea-Bird (Top) SBE 41 SN0748 conductivity sen- sor calibration history showing 37 com- plete calibrations over fve years (April 3 to June 8). (Bottom) SBE 41 SN0748 temperature sensor calibration history showing 37 complete calibrations over fve years (April 3 to June 8) . Iver3 Autonomous Underwater Vehicles Side Scan Bathy Water Quality Magnetometer www.ocean-server.com +1 508-878-0550 Rapid Data Collection For Coastal Applications