Correction for Systematic Errors in the Global Dataset of Temperature Profiles from Mechanical Bathythermographs
Correction for Systematic Errors in the Global Dataset of Temperature Profiles from Mechanical Bathythermographs
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DOI：
10.1175/jtech-d-19-0205.1
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发表时间：
2020-05-01
影响因子：
2.2
通讯作者：
Cheng, Lijing
中科院分区：
文献类型：
--
作者：
Gouretski, Viktor;Cheng, Lijing
覆盖几十年时间的均匀、一致、高质量的原位温度数据集对于探测海洋气候变化至关重要。从 1940 年至今，本研究通过将机械深海温度计 (MBT) 的温度剖面数据与南森瓶铸件和电导率-温度深度 (CTD) 剖面仪获得的参考数据进行比较，调查了这些数据的质量。这一比较揭示了 MBT 测量中存在显着的系统误差。 1980 年之前，全球平均 MBT 偏差高达 0.2 摄氏度，1980 年后减少到小于 0.1 摄氏度。导出了一种新的 MBT 数据经验校正方案，其中 MBT 校正与国家、深度和时间相关。将新的 MBT 校正方案与文献中早期提出的三种方案进行比较表明，新方案具有更好的性能。偏差的减少增加了全球海洋数据库的同质性，这对于气候变化相关的研究最为重要，例如改进对海洋热含量变化的估计。
A homogeneous, consistent, high-quality in situ temperature dataset covering some decades in time is crucial for the detection of climate changes in the ocean. For the period from 1940 to the present, this study investigates the data quality of temperature profiles from mechanical bathythermographs (MBT) by comparing these data with reference data obtained from Nansen bottle casts and conductivity-temperature-depth (CTD) profilers. This comparison reveals significant systematic errors in MBT measurements. The MBT bias is as large as 0.2 degrees C before 1980 on the global average and reduces to less than 0.1 degrees C after 1980. A new empirical correction scheme for MBT data is derived, where the MBT correction is country, depth, and time dependent. Comparison of the new MBT correction scheme with three schemes proposed earlier in the literature suggests a better performance of the new schemes. The reduction of the biases increases the homogeneity of the global ocean database being mostly important for climate change-related studies, such as the improved estimation of the ocean heat content changes.