2020-01-14   Downloaded this file from https://www.usap-dc.org/readme/601422 ,  for 'version 2' of data

USAP-DC Dataset# 601422
2021-01-12
https://api.datacite.org/dois/10.15784/601422

abstract:
Ocean profile data from a SeaBird SBE 911plus CTD package deployed on the NBP1704 PIPERS cruise in the Ross Sea (Apr 11 to Jun 10, 2017). 

Instruments and devices:
A SeaBird SBE 911plus CTD package was used to acquire vertical profiles of ocean data along the NBP1704 cruise track. 

Acquisition procedures:
This package was maintained and operated by the Antarctic Support Contractor (ASC) using SeaBird SBE 911plus data acquisition hardware and software.

Content and processing steps:
The CTD sensor data are provided as individual downcast, upcast & bottle data in tab-delimited ascii format (*.txt).  The data included are: Pressure (db), Depth (m), Time (year day), Latitude (deg), Longitude (deg), Temperature (deg C), Conductivity (S/m), Dissolved Oxygen (ml/l), Potential Temperature (deg C), Salinity (psu), Sigma-theta (kg/m3), Fluorometer (mg/m3), PAR, Beam Transmission (%), Beam Attenuation (1/m).  For casts 1-9, the SOCCOM FLBB1/FLBB2 sensor data are also included, with casts 8-9 being ‘dark’.  The bottle data also include the NISKIN bottle number (in the first column).  A no data value is designated as NaN ('not-a-number').   The data are also provided as a Matlab structure array and includes the downcast, upcast & bottle sensor data, headers to those data sets, date/time, lat, lon, and CTD (cast) number.  A no data value is designated as NaN.  See also the included Readme file (nbp1704_final_readme.rtf).

The dual T/C/O2 sensors were pre- and post-cruise calibrated by SeaBird.  All post-cruise corrections based on the SeaBird calibration data, as well as discrete O2 titration data, were performed by Principle Investigator Dr. Sharon Stammerjohn (CU-Boulder), NSF/OPP 13-41606. See also the included Readme file (nbp1704_final_readme.rtf).

Limitations and issues:
The CTD package performed well, with just a few exceptions as noted in the Readme file (nbp1704_final_readme.rtf). The CTD was re-terminated several times throughout the cruise.  Modulo errors began appearing, starting with cast 33.  Casts 33, 44 and 45 were repeated due to extreme error reporting; repeat casts 44 and 45 were still slightly affected. Other casts affected by modulo errors (spikes) were casts 49 and 53.  Many of the C and O2 upcast profiles had spikes in the top 1-3 meters: casts 1, 3, 5, 8, 10, 12, 13, 15, 18, 20, 22, 23, 24, 27, 31, 47, 52, 57.  All bad data (spikes) were replaced by NaN.

The NBP1704 CTD sensor data were originally posted on USAP-DC on 7/11/2019.  Errors in the CTD sensor data were subsequently detected in two variables:  Conductivity and Dissolved Oxygen.  Those errors were corrected (1/12/2021), and ‘version 2’ of these data were uploaded to the USAP-DC, replacing the original version with this updated/corrected data set.

Checkboxes:
* All the data are referenced in time and space.
* The data column, properties, and attributes listed/used in the data files are explained either in the description and/or the data files themselves.
* Graphs and maps (if provided) have legends.