Oceanographic profile temperature and salinity data using underway CTD, collected by the Graduate School of Oceanography, University of Rhode Island, cruise EN492, North Atlantic Ocean, 2011-04 to 2011-05 (NODC Accession 0116845)

The dataset consists of 79 Underway CTD (UCTD) casts in the region north of Flemish Cap. The UCTD is an un-pumped profiling CTD, manufactured by the Oceanscience Group, that can be deployed from a moving ship. The UCTD measures temperature, conductivity, and pressure at 16 Hz. The pressure and its time derivative (descent rate) were low-pass filtered with a filter cutoff period of 2 s. The temperature and conductivity signals were also filtered, but with the filter cutoff period set to 0.25 s. Alignment of the temperature and conductivity was performed as a function of the instrument descent rate using an empirical relationship. Because of the rapid descent rate of the UCTD (up to 4 dbar/s), the measured temperature was corrected for the effect of viscous heating. The effect of the thermal mass of the conductivity cell was accounted for using the standard correction with the parameters determined as a function of the local instrument descent rate. The processed temperature, conductivity, and pressure were used to compute salinity, potential temperature, and potential density. Finally, the data were averaged into 1 dbar bins.

本数据集包含弗拉芒海台（Flemish Cap）以北海域的79组走航式温盐深剖面仪（Underway CTD, UCTD）投测剖面。走航式温盐深剖面仪（UCTD）为海洋科学集团（Oceanscience Group）生产的无泵式剖面温盐深仪，可在移动作业船舶上布放。该仪器以16 Hz的频率同步采集温度、电导率与压力数据。随后对压力及其时间导数（即仪器下沉速率）实施低通滤波处理，滤波截止周期为2秒；温度与电导率信号同样经过滤波，滤波截止周期设为0.25秒。研究人员基于仪器下沉速率，通过经验关系完成温度与电导率信号的对齐校正。鉴于UCTD的下沉速率极快（最高可达4 dbar/s），需对实测温度进行粘滞加热效应校正。同时，采用标准校正方法，并结合随仪器本地下沉速率变化的校正参数，补偿了电导池热质量带来的信号影响。经预处理后的温度、电导率与压力数据被用于计算盐度、位温与位密。最终，所有数据按1 dbar的压力间隔进行平均分箱处理。