Milne Fiord CTD (Conductivity, Temperature, Depth) profiles

Conductivity, Temperature, Depth (CTD) profiles taken in Milne Fiord during summer (July) fieldwork campaigns. Profiles were collected primarily using an RBR XR620 CTD, but also with an RBR Concerto and an Idronaut Ocean Seven 304Plus during some campaigns. The CTD was deployed at sites accessed by foot, snowmobile, and helicopter through augered holes in the sea ice or epishelf lake ice or through natural leads or fractures in the Milne Ice Shelf or Milne Glacier tongue, as well as through leads in the sea ice offshore. The CTD was lowered on a 2.5 mm synthetic line using a hand reel to a nominal depth of 15 m for 2 minutes to equilibrate, raised to the surface, and then lowered at 0.5-1.0 m/s to the bottom, then raised at 1-2 m/s to the surface. Raw data were processed in MATLAB based on steps outlined in the Seabird Data Processing Manual (Seabird Scientific, 2017) and Halverson et al. (2017). Processing steps included an atmospheric pressure correction based on in-air pressure readings, low-pass filtering with a time constant, conductivity-temperature alignment to reduce salinity spiking by advancing temperature relative to pressure, selection of downcast, loop editing, calculation of derived variables using TEOS-10 Gibbs Seawater (GSW) Oceanographic Toolbox, and bin averaging (0.2 m bins). Only processed downcasts are included in the dataset. This archive is for CTD after 2020. CTD before 2020 can be found at https://doi.org/10.21963/12102

本数据集包含米尔内峡湾（Milne Fiord）夏季（7月）野外作业期间采集的电导率-温度-深度（Conductivity, Temperature, Depth, CTD）剖面数据。剖面数据主要通过RBR XR620型CTD采集，部分作业时段也使用了RBR Concerto与Idronaut Ocean Seven 304Plus型号设备。CTD的布放点位可通过步行、雪地摩托与直升机抵达，布放方式包括：在海冰或冰架下湖冰盖上钻孔，或借助米尔内冰架（Milne Ice Shelf）、米尔内冰川舌（Milne Glacier tongue）上的自然冰间水道与冰裂缝，以及近海海冰中的冰间水道。CTD通过2.5毫米合成缆绳由手动绞车下放：先下放至标称深度15米处静置2分钟以完成设备平衡，随后升至海面；再以0.5~1.0米/秒的速度下放至海底，最后以1~2米/秒的速度升回海面。原始数据基于《Seabird数据处理手册》（Seabird Scientific，2017）与Halverson等人（2017）提出的处理流程，在MATLAB环境中完成处理。处理流程包括：基于空中压力读数开展大气压力校正、采用时间常数进行低通滤波、通过将温度数据相对于压力数据前移以降低盐度尖峰的电导率-温度校准、下行剖面筛选、循环编辑、使用TEOS-10吉布海水（Gibbs Seawater, GSW）海洋学工具箱计算衍生变量，以及0.2米间隔的分箱平均。本数据集仅包含经过处理的下行剖面数据。本归档数据为2020年之后采集的CTD数据；2020年之前的CTD数据可通过链接https://doi.org/10.21963/12102获取。