Exploration of Calibration Methods for Ocean NTC Thermistor Thermometers
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摘要: 应对海洋温度高精度测量需求,结合国家温度基准水三相点和镓熔点装置对海洋用国产负温度系数(NTC)热敏电阻元件长期稳定性进行考察,通过引入等温热管技术的恒温槽并采用“瞬时比较法”对NTC热敏电阻温度计进行校准方法探索。结果表明,经过筛选的国产NTC热敏电阻元件稳定性可达到海洋领域所需水平;常规封装工艺易导致NTC热敏电阻温度计稳定性下降,进行多次热循环是提高其稳定性的有效手段;校准点数量和分布对校准水平具有较大影响;存在高性能温度计在各点校准偏差很小且几乎不受选点分布影响。研究结果有助于建立NTC热敏电阻温度计评测方法和控制标准,为海洋测温领域计量体系发展指明方向。Abstract: To meet the demand for high-precision measurement of ocean temperatures, the long-term stability of domestic Negative Temperature Coefficient (NTC) thermistor elements for ocean temperature measurement was investigated by using the national temperature reference of water triple point and gallium melting point. The calibration method for NTC thermistor thermometers was explored by introducing the thermostatic bath with the isothermal heat pipe technique and adopting the “instantaneous comparison method”. The results showed that the domestic NTC thermistor elements can have a half-year stability better than 1 mK, but long-term evaluation is still necessary. The conventional packaging processes can easily decrease the stability of NTC thermistors, and multiple thermal cycles are an effective way to improve the stability. The number and distribution of calibration points have a great influence on the calibration. But there are high-performance thermometers with little calibration deviation, hardly affected by the distribution of selected points. The analysis of these thermometers can help establish NTC thermistor evaluation standards and shed light on the development of the field of ocean temperature measurement.
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Key words:
- ocean temperature /
- NTC thermistor /
- temperature measurement /
- long-term stability /
- calibration method /
- Uncertainty
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表 1 NTC热敏电阻温度计校准不确定度
Table 1. Calibration uncertainties of NTC thermistor thermometers
不确定度来源 标准不确定度/mK 多次测量重复性 0.15 恒温槽稳定性 0.11 恒温槽均匀性 0.11 SPRT校准不确定度 0.30 合成标准不确定度 0.37 扩展不确定度 0.8(k=2) 表 2 4点校准不同选点统计结果
Table 2. Statistical result of NTC thermistor thermometers calibration by using four measurement points
排序 选点分布 NTC数量 1 −5 5 25 35 68 2 −5 0 20 35 65 3 −5 5 20 35 63 4 −5 0 25 35 61 5 −5 10 20 35 60 6 −5 10 25 35 60 7 −5 15 20 35 57 8 0 5 25 35 57 9 −5 15 25 35 56 10 0 10 25 35 56 表 3 5点校准不同选点统计结果
Table 3. Statistical result of NTC thermistor thermometers calibration by using five measurement points
排序 选点分布 NTC数量 1 −5 0 15 25 35 79 2 −5 0 15 30 35 77 3 −5 0 10 25 35 76 4 −5 0 15 20 35 71 5 −5 0 10 30 35 70 6 −5 0 20 25 35 70 7 −5 0 20 30 35 70 8 −5 5 15 30 35 70 9 −5 5 15 25 35 68 10 −5 5 20 30 35 65 表 4 6点校准不同选点统计结果
Table 4. Statistical result of NTC thermistor thermometers calibration by using six measurement points
排序 选点分布 NTC数量 1 −5 0 10 20 30 35 115 2 −5 0 5 20 30 35 110 3 −5 0 10 25 30 35 107 4 −5 0 10 15 30 35 106 5 −5 0 15 20 30 35 106 6 −5 0 5 15 30 35 103 7 −5 0 10 20 25 35 101 8 −5 0 5 20 25 35 99 9 −5 0 5 15 25 35 98 10 −5 0 15 25 30 35 97 -
[1] Sciences E P, University H, Cambridge, et al. Global Ocean Integrals and Means, with Trend Implications[J]. Annual Review of Marine Science, 2015. [2] Johnson G C, Lyman J M, Loeb N G. Improving estimates of Earth's energy imbalance[J]. Nature Climate Change, 2016, 6(7): 639-640. doi: 10.1038/nclimate3043 [3] Talley L D, Feely R A, Sloyan B M, et al. Changes in Ocean Heat, Carbon Content, and Ventilation: A Review of the First Decade of GO-SHIP Global Repeat Hydrography[J]. Annual Review of Marine Science, 2015, 8(1). [4] Rasmussen L L, Carter M L, Flick R E, et al. A century of Southern California coastal ocean temperature measurements[J]. Journal of Geophysical Research: Oceans, 2020, 125(5): e2019JC015673. [5] Guang L, Liang G, Chunlong L, et al. Uncertainty propagation in the calibration equations for NTC thermistors[J]. Metrologia, 2018, 55(3): 437-445. doi: 10.1088/1681-7575/aaba8e [6] 陈朝阳. 中科院航天海洋测温NTC热敏电阻器研究系列成果获得广泛应用[J]. 科技促进发展, 2016, 12(4): 488-493. [7] Joung W, Gam K. Pearce J V. Pressure dependence of the reference deep-ocean thermometers[J]. Metrological Applications, 2020, 27(1): e1870. [8] Zilberman N, Roemmich D. The Argo program samples the deep ocean[J]. US CLIVAR Variat, 2017, 2: 29-33. [9] McTaggart K E, Johnson G C, Johnson M C, et al. Notes on CTD/O2 data acquisition and processing using Sea-Bird hardware and software (as available)[J]. The GO‐SHIP Repeat Hydrography Manual: A Collection of Expert Reports and Guidelines, IOCCP Report 15, 2010. [10] Rudtsch S, Von Rohden C. Calibration and self-validation of thermistors for high-precision temperature measurements[J]. Measurement, 2015, 76: 1-6. [11] Uchida H, Nakano T, Tamba J, et al. Deep ocean temperature measurement with an uncertainty of 0.7 mK[J]. Journal of Atmospheric and Oceanic Technology, 2015, 32(11): 2199-2210. doi: 10.1175/JTECH-D-15-0013.1 [12] 国家海洋标准计量中心. 温盐深测量仪检定规程: JJG 763-2002[S]. 北京: 中国计量出版社, 2002. [13] Ying Liu, Yiping Liu, Zhang Wen, et al. The Study of Temperature Calibration Method for NTC Thermistor[C]. 2020 IEEE 4th International Conference on Frontiers of Sensors Technologies (ICFST). IEEE, 2020: 50-53. [14] Guang Liu, Liang Guo, Chunlong Liu, et al. Evaluation of different calibration equations for NTC thermistor applied to high-precision temperature measurement[J]. Measurement, 2018, 120: 21-27. doi: 10.1016/j.measurement.2018.02.007 [15] White D R, Hill K, del Campo D, et al. Guide on secondary thermometry: Thermistor thermometry[R]. Bureau International des Poids et Mesures: Paris, France, 2014.