README FILE FOR 2018 BERING STRAIT CTD DATA             Version 26th May 2019
                                                        Updated 23rd Oct 2019
=============================================================================
****** Oct 2019 update:
It was found there was a processing error in the 26th May 2019 version of this
data set, whereby the processed data were calibrated using an old calibration file.
This new release of the data, labelled v2, are corrected for this error.
To be sure you are using the correct data, look in the header file for the
line: # Derive_in ... and check the XMLCON filestarts BSTRAIT2018
To distinguish from prior submission, corrected data filenames contain the
letters v2.
This error affected only the converted Oxygen values in the data (columns 22-25).
The erroneous data were:
- in Ox1, too low by around 0.6ml/l and 9% saturation
- in Ox2, too high by around 0.2ml/l and 3% saturation.
leading to an Ox2-Ox1 sensor difference of ~13% saturation
Once corrected, the Ox2-Ox1 sensor difference is ~1% saturation
******************************************************************************

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This is an archive of CTD data from the 2018 Bering Strait mooring cruise.

The cruise was funded by the NSF-Arctic Observing Network grants:
- PLR-1304052 (PIs: Woodgate, Heimbach and Nguyen), and
- PLR-1758565 (PIs: Woogate and Peralta-Ferriz). 

The data are from a ~ 10 day cruise 
- on the US vessel Norseman II 
- from 10th-19th August 2018 
- sailing from and to Nome, Alaska, USA 
- to the Bering Strait and southern Chukchi Sea.
The cruise was also to service oceanographic moorings in the strait and those
data are archived separately. 

A total of 142 casts were taken and are included in this archive.
No water samples were taken during this cruise. 
Stations were taken in US waters near mooring locations and on sections
in the Bering Strait and southern Chukchi Sea.  See cruise report for
map, station locations, calibration, and processing details. 

The data are taken using an SBE911p system, recording 
- pressure 
- temperature (dual system)
- conductivity (dual system)
- oxygen (dual system)
- fluorescence
- turbidity.

For an overview of previous and on-going Bering Strait mooring work,
please see http://psc.apl.washington.edu/BeringStrait.html.

For details of the measurements and their interpretation, please see:
   Woodgate, R.A., K.M.Stafford and F.G.Prahl (2015) A synthesis of
   year-round interdisciplinary mooring measurements in the Bering
   Strait (1990-2014) and the RUSALCA years (2004-2011), Oceanography
   28(3):46-67, doi:10.5670/oceanog.2015.57

Please cite that reference for the data. 

For queries, please contact:
   Rebecca Woodgate   woodgate@uw.edu   (206) 221-3268
   Polar Science Center, Applied Physics Lab, University of Washington
   1013 NE 40th, Seattle, WA  98105-6698   USA

------------------------------------------------------------------------------

Meta data
=========

1) Platform: SBE911p CTD system on board the RV Norseman II

2) Project title: Bering Strait

3) Data collection dates: 10th-19th August 2018

4) PI:   Rebecca Woodgate (woodgate@uw.edu)

5) Data collection method:
     Hydrographic casts (no water samples)

6) Data calibration method:
     Instrument calibrated by manufacturers prior to deployment.
        Pressure calibrated March 2018
        Temperature calibrated February 2018
        Conductivity calibrated February 2018
        Oxygen calibrated February 2018
        Fluorescence / Turbidity calibrated  March 2010
     All times are given in GMT.
     All positions and times are from ship's aft A-frame NMEA.
     For SBEs, calibration and processing details are in file header.

7) Instrumentation used:
     Sea-Bird SBE911p system sampling at 24Hz with
         two SBE3F temperature sensors
         two SBE4C conductivity sensors
         two SBE43 Oxygen sensors
         one Wetlabs FLNTURT fluorescence/turbidity sensor
         one Benthos altimeter (data only intermittently reliable)
         two SBE pumps

8) Quality control procedures:
     Basic quality control provided by Rebecca Woodgate.
     CTD processing by SBE software as described in cruise report and file headers. 
     Fluorescence/turbidity sensor cleaned prior to each cast. 

9) Data format:
     Bstrait18nnn.hex data - as collected
     Bstrait18nnn.XMLCON - calibration coefficients
     Bstrait18nnnA00B15AdvOx2CTML7m4m18p5mndpDv2MF17 
                         - processed data (at native time resolution)
     Bstrait18nnnA00B15AdvOx2CTML7m4m18p5mndpDv2MF17BADCS010 
                         - processed data averaged to 1m bins from downcast
     nnn gives cast number
     (v2 signifies Oct 2019 correction explained above)
     Time (GMT), Latitude and longitude are recorded in the data files	
      
10) Data collection problems:
	Generic:  - the Benthos altimeter only returned believable data for some casts.
       Thus water depths should be taken from the event log in the cruise report.
     Oxygen sensors show an offset of ~ 2% saturation. As no water samples were taken
       we cannot ascertain which sensor is correct.
     Salinity (from conductivity) senors show an offset of 0.006psu, decreasing during
       the cruise.  As no water samples were taken we cannot ascertain which sensor is correct.
     CTD hit  bottom on cast 83, thus the following data are bad:
		Cast 83, all primary sensors, up cast 
		Cast 84, all primary sensors, down & up cast 
           Cast 85, all primary sensors, down & up cast 

11) Other related data sets:
       This data set is a part of a suite of measurements made in the
       Bering Strait almost continuously since 1990.  Mooring data have
       already been archived via the SBI project, managed by JOSS/EOS,
       and at NODC.
       For details see
        http://psc.apl.washington.edu/BeringStrait.html
        http://www.eol.ucar.edu/projects/sbi/
        http://sbi.utk.edu/
        http://www.nodc.noaa.gov
       Since 2000, CTD sections have been run in the Bering Strait on
       the mooring cruises.  These data are also accessible via the http
       links above.

12) Conditions for use or citation:
       Data freely available
       Please, as a courtesy, contact the PIs before using these data and cite as
           Woodgate, R.A., K.M.Stafford and F.G.Prahl (2015) A synthesis of
             year-round interdisciplinary mooring measurements in the Bering
             Strait (1990-2014) and the RUSALCA years (2004-2011), Oceanography
             28(3):46-67, doi:10.5670/oceanog.2015.57

13) Data qualifications or warnings:
       See also Data collection problems.
       SBE data: Standard Sea-Bird limitations apply
           - pressure 0.015% of FSR (6800m), i.e., ~ 1m (calibration suggests 0.6m)
           - temperature 0.001degC
           - Conductivity 0.0003S/m
               Combined errors equivalent to salinity error of ~0.008psu

14) Grant numbers:
      Work funded by:
      - National Science Foundation (NSF) Arctic Observing Network (AON)
      program, grant PLR-1304052 (PI: Woodgate, Heimbach and Nguyen)
      - National Science Foundation (NSF) Arctic Observing Network (AON)
      program, grant PLR-1758565 (PI: Woodgate and Peralta-Ferriz)

15) Sample repository locations:
        National Ocean Data Center (http://www.nodc.noaa.gov)
        University of Washington (http://psc.apl.washington.edu/HLD)

16) Please use the following citation for these data:
   Woodgate, R.A., K.M.Stafford and F.G.Prahl (2015) A synthesis of
       year-round interdisciplinary mooring measurements in the Bering
       Strait (1990-2014) and the RUSALCA years (2004-2011), 
       Oceanography, 28(3):46-67, doi:10.5670/oceanog.2015.57

==============================================================================

==============================================================================

FILE LISTING
=============

Total number of files:  572 including 3 subdirectories.
Total number of casts: 142

Size (b)   Name
---------  ----
= Metadata file (1 file)
      8445  Bering_Strait_CTD_August2018_NSFAON_ReadMe_versOct2019.txt

= Cruise report (1 file)
 7397725 May 23 22:16 BeringStrait2018CruiseReport_Norseman2_23rdMay2019withEL.pdf

.. and the 3 subdirectories: 

== One subdirectory of SBE .hex and .XMLcon calibration files (284 files)
and one generic .XMLcon file (1 file)
./BeringStraitCTD_hexandXMLCON:
Bstrait18nnn.hex and BSTRAIT18nnn.XMLCON where nnn is cast number, e.g.,
 779087 Aug 11  2018 Bstrait18001.hex
   9969 Aug 15  2018 BSTRAIT18001.XMLCON

== One subdirectory of processed data at native time resolution (142 files)
./BeringStraitCTD_processed_v2:
Bstrait18nnnA00B15AdvOx2CTML7m4m18p5mndpDv2MF17.cnv where nnn is cast number, e.g.,
 2683426 Oct 23  2019 Bstrait18001A00B15AdvOx2CTML7m4m18p5mndpDv2MF17v2.cnv

== One subdirectory of processed data at averged to 1m bins from the down cast (142 files)
./BeringStraitCTD_Binaveraged_v2:
Bstrait18nnnA00B15AdvOx2CTML7m4m18p5mndpDMF17BADCS010.cnv where nnn is cast number, e.g.,
 18513 Oct 23  2019 Bstrait18001A00B15AdvOx2CTML7m4m18p5mndpDMF17v2BADCS010.cnv

+++++++++ END OF FILE LISTING ++++++++++++++++++++++++++++++ 