CTD data from NERC Changing Arctic Ocean Cruise JR17005 on the RRS James Clark Ross, May-June 2018 (version 2).

This dataset contains a total of 72 CTD casts that were completed from the RRS James Clark Ross (cruise number JR17005), between the 13th May 2018 and 6th June 2018. The cruise was part of the Changing Arctic Ocean Programme funded by the Natural Environment Research Council, UK (www.changing-arctic-ocean.ac.uk). Three main transects were completed. The first from the deep water of the Greenland Basin up into the Norsk Trough on the East Greenland shelf at a latitude of 76 degN. A second transect was completed at 79 degN across the Fram Strait, starting at 10 degW on the East Greenland Shelf and finishing a few miles off the coast of Svalbard. A third transect was completed to the south of Svalbard within Storfjorden at 77 degN. Raw data were initially extracted and processed using Seabird Data Processing Software (v7.26.7). Modules DatCnv, WildEdit, Filter, AlignCTD, CellTM, Derive and BottleSum were all run. Custom Matlab routines were then used to apply a deep oxygen hysteresis correction, to remove out of water and surface soak values, to filter anomalous data points and to average the profiles onto a 1 db pressure grid. Each 1 db averaged profile (downcast) contains the following variables: latitude, longitude, day number, pressure (db), depth (m), primary and secondary temperature (degC), conductivity (mS cm^-1), salinity (psu) and potential density (kg m^-3), chlorophyll-a fluorescence (mg m^-3), beam attenuation (m-1), beam transmission (%), photosynthetically active radiation (microE m^-2 s^-1), oxygen concentration (micromol l^-1) and altimetry (metres above the bottom). Files are also provided that contain 5 second averages of all the above variables around the times of bottle firings (on the up casts). The SBE43 oxygen sensor was calibrated against Winkler titration samples (taken in triplicate) from 20 l Niskin bottles mounted onto the frame. Salinity samples analysed on a Guildline Autosal instrument were used to calibrate the salinity profiles.

本数据集共计包含72次CTD（Conductivity-Temperature-Depth，温盐深仪）站位测量数据，采集于2018年5月13日至2018年6月6日期间，由英国皇家研究船“詹姆斯·克拉克·罗斯号”（RRS James Clark Ross）执行的JR17005航次获取。该航次为英国自然环境研究理事会（Natural Environment Research Council, NERC）资助的“变化北冰洋计划”（Changing Arctic Ocean Programme，www.changing-arctic-ocean.ac.uk）的组成部分。
本次航次共完成三条主要断面测量。第一条断面从格陵兰盆地深水区北上，抵达东格陵兰陆架的诺斯克海槽（Norsk Trough），纬度为76°N。第二条断面位于79°N的弗拉姆海峡（Fram Strait），起自东格陵兰陆架的10°W海域，终至斯瓦尔巴德群岛沿岸外数英里处。第三条断面位于斯瓦尔巴德群岛以南的斯托尔峡湾（Storfjorden），纬度为77°N。
原始数据最初通过海鸟数据处理软件（Seabird Data Processing Software, v7.26.7）进行提取与处理，依次运行了DatCnv、WildEdit、Filter、AlignCTD、CellTM、Derive及BottleSum模块。后续采用自定义Matlab脚本完成了一系列预处理操作：包括深层氧滞后校正、剔除脱离水体及水面浸泡的异常数据、过滤异常测点，并将剖面数据插值至1db压力网格进行平均。
每条经1db压力网格平均的下行剖面（downcast）包含以下变量：纬度、经度、日序数、压力（db）、深度（m）、一次及二次温度（℃）、电导率（mS cm⁻¹）、盐度（psu）、势密度（kg m⁻³）、叶绿素a荧光强度（mg m⁻³）、光束衰减系数（m⁻¹）、光束透射率（%）、光合有效辐射（μE m⁻² s⁻¹）、氧浓度（μmol l⁻¹）以及测高数据（距底高度，m）。
此外还提供了对应采水瓶发射时刻（上行剖面时段）的所有上述变量的5秒平均数据文件。
SBE43型氧传感器通过挂载于采样框架上的20L尼斯金（Niskin）采水瓶采集的三份平行水样的温克勒滴定（Winkler titration）结果完成校准。盐度剖面的校准则基于采用Guildline Autosal仪器分析的盐度水样完成。