Continuous thermosalinograph oceanography along RV POLARSTERN cruise track PS122/3

Raw data acquired by two thermosalinographs (SBE21, SeaBird GmbH) on board RV Polarstern were processed to yield a calibrated and validated data set of temperature, conductivity and salinity during expedition PS122/3. Both sensors were equipped with a more accurate external temperature sensor (SBE38, Sea-Bird GmbH). Data were downloaded from the DAVIS SHIP data base (https://dship.awi.de) with a resolution of 1 sec. The raw hex data were converted to temperature and conductivity while a sensor drift correction was applied using calibration coefficients from before and after the expedition. Salinity was calculated according to the instructions from the Practical Salinity Scale PSS-78, using the obtained (internal) temperature and conductivity data and a pressure of 11 dbar which represents the water depth of the inlet of the TSG system on Polarstern. Processed data are provided as 10min means of salinity and water temperature aligned with position data taken from master track of the respective cruise. A speed filter was not applied to the PS122 dataset because of the slow drift speed. This slow movement may lead to an overestimation of the mixed-layer temperature; in particular, small heat fluxes from the ship may raise the temperature in adjacent water in the lee, i.e. during times of drift in the direction opposite to the TSG inlet. The effect is expected to be small, but can potentially be higher than the accuracy of the temperature measurement. Further details and evaluation of the data is outlined in the data processing report found at the EPIC repository under URL (https://hdl.handle.net/10013/epic.7fffb528-06bd-48ae-8489-cea0444c4eab).

本研究对搭载于极星号（RV Polarstern）科考船的两台船载温盐仪（thermosalinograph，SBE21，SeaBird GmbH）在航次PS122/3期间采集的原始数据进行处理，最终得到经校准且验证有效的温度、电导率与盐度数据集。两台传感器均配备了精度更高的外置温度传感器（SBE38，Sea-Bird GmbH）。数据从DAVIS SHIP数据库（https://dship.awi.de）下载，时间分辨率为1秒。原始十六进制数据被转换为温度与电导率数据，并利用航次前后获取的校准系数完成传感器漂移校正。盐度依据实用盐标（Practical Salinity Scale PSS-78）的规范进行计算，采用获取的（内置）温度与电导率数据，以及代表极星号TSG系统进水口水深的11分巴（dbar）压力值。处理后的数据以盐度与海水温度的10分钟平均值形式输出，并与对应航次主航迹获取的位置数据匹配对齐。由于本航次漂移速度较慢，未对PS122数据集应用速度滤波。该低速运动可能导致混合层温度被高估：具体而言，当科考船以与TSG进水口相反的方向漂移时，船体产生的微小热通量会使下风侧邻近水体的温度升高。该影响预计较小，但仍有可能超出温度测量的精度范围。有关该数据集的更多细节与评估内容，详见EPIC知识库中收录的数据处理报告，链接为https://hdl.handle.net/10013/epic.7fffb528-06bd-48ae-8489-cea0444c4eab。