Evaluation of calibration and measurement uncertainty of temperature sensors of CTD-probe “Sea Bird”

 A.N. Ramazin

Russian Federal Research Institute of Fisheries and Oceanography (VNIRO), Russian Federation, Moscow, V.Krasnoselskaya St., 17

Email: ramazin@vniro.ru

DOI: 10.33075/2220-5861-2018-4-33-42

UDC 551.46


     Some results of experimental studies of metrological characteristics of temperature sensors made with using a complex of foreign precision calibration equipment are considered on five samples of various models of Sea Bird СTD probes.

      The analysis of the contribution of individual components into total uncertainty is given. The values of the total uncertainty of SPTS uΣO and the total uncertainty due to the spatial-temporal heterogeneity of the temperature field in the working area of the calibration uΣT could be considered as practically constant or slightly changeable values. Their total value will mainly determine the magnitude of the total uncertainty in the calibration of temperature sensors of a measuring instrument in the thermal tank.

      For these models, the experimental data were used to calculate characteristics of the dependences of the sensitivity coefficient ∂f/∂T, the standard deviation of the input signal (frequency) s(fi), and the sensor readings on the temperature in the thermal tank. Their functional relationship is analyzed.

    The analysis of the temporal walk of SPTS readings and temperature sensors of СTD probes “Sea Bird” between the calibrations is performed. The time maintenance of the SPTS calibration characteristics, which is the working standard of the 0th category, does not exceed 0.1 mK/year. The temporal annual maintenance of the calibration characteristics of the considered models of CTD probes between two calibrations does not exceed the value of the extended calibration uncertainty.

Keywords: reusable measurements, temperature sensor, calibration, CTD probe, standard, total and extended uncertainty, sensitivity coefficient, standard deviation, uncertainty interval, time walk.

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