Ocean Carbon and Biogeochemistry Data System

SOFeX 2002 Polar Star cruise
Data processing notes for SOFEX Seabird CTD profile data

2 May 2007: Prepared for OCB data system by Terry McKee (PO Dept., Woods Hole Oceanographic Institution)

Sea-Bird SBE 911 CTD Profiles ~ stations 1-6
Original binary Sea-bird data files were transferred from Ken Buesseler's post-cruise CD-ROM to dmoserv1 and then to processing computer.

Part one: Producing clean one-decibar=averaged profile:

Sea-Bird\SBEDataProcessing-Win32 version 5.34b was used.
Program ConReport indicated that sensors were Primary Temperature, Primary Conductivity, Pressure, Secondary Temperature, Secondary Conductivity, PAR, Fluorometer, Transmissometer.
Stations 2, 3, and 3A have an altimeter.
Station 1 had two altimeters.
For stations 4 and 6, data had been converted from binary to ascii. No other processing had been done.
Pressure had not been included in .cnv file though there was a pressure sensor.
An xls indicates that a preliminary comparison of bottle salts and ctd salinities had been done.
To produce a final one-decibar-averaged series, files were run through the standard Sea-bird process:

• # datcnv datcnv_skipover = 0
• # alignctd_adv = c1mS/cm 0.073
• # wildedit_pass1_nstd = 2.0 # pass2_nstd = 20.0# pass2_mindelta = 0.000e+000 # _npoint = 100 _vars = all
• # celltm_alpha = 0.0300, 0.0300 _tau = 7.0000, 7.0000 _temp_sensor_use_for_cond = primary, secondary
• # filter_low_pass_tc_A = 0.030 _low_pass_tc_B = 0.150 _low_pass_A_vars = all except pressure and depth _low_pass_B_vars = prDM depSM
• # loopedit_minVelocity = 0.100 _surfaceSoak: minDepth = 5.0, maxDepth = 20, useDeckPress = 1 _excl_bad_scans = yes
• # binavg_bintype = decibars _binsize = 1 _excl_bad_scans = yes _skipover = 0 _surface_bin = no, min = 0.000, max = 0.000, value = 0.000
• # Derive_ salinity, potential temperature, and densities.
• # split_excl_bad_scans = yes # file_type = ascii

Final CTD cast header record from processed file:
CTD cast 6 header

Data were plotted with matlab to compare early un-edited version with final 1db-averaged version.

NOTE: For Station 1, Second altimeter was ignored, since processing it was incompatible with current software.

Comparing CTD salinity and bottle salinity: In deeper water agreement is good.

Part Two: Converting from Seabird .cnv format to OCB database format
1. Create lookup table to match Seabird parameter names to OCB parameter names.
2. Modify program check_write_params.plx to read Seabird .cnv format.
3. Run in check mode first to find inconsistent data setup.
4. Standardize data setup, i.e., pad missing altimeter data to nd for 4,5,6.
5. Convert files to OCB.
6. Compare converted files to original files using extrema for each variable.

QC NOTE: Removed 3 -999 (no data) records at surface of 1, 2, and 6

Final files are called SOFEX-x.OCBf (f for final prettied-up version.)
Prepare .hdr and .info files for dataset.
Dos2unix *.OCBF; tar/gzip and send to cchandler on 4/25/2007 for inclusion in OCB database.

Contact: Ken Buesseler (WHOI)

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