



     GP8-06-KA
     NOAA Ship KA'IMIMOANA
     Kwajalein, Marshall Islands - Honolulu, HI
     November 4-27, 2006

     Chief Scientist: Paul Freitag
     Survey Department: AST Tonya Watson
     ET Department: Mike Hilton 
     CTD Personnel: AST Tonya Watson, Robert Harris
     Final Processing: Kristy McTaggart


     ACQUISITION:

     Thirty-five CTD profiles were collected at 35 stations during this cruise.
     Eighteen profiles were collected from 8N to 8S along 165E.  Seventeen
     profiles were collected from 8S to 3N along 180.  CTDs from 4N-12N, 180
     were skipped as the ship was diverted back to Honolulu because the RHIB
     was down.  Five casts were deep (>3000m) and the rest were to 1000m.

     It was reported that there were many modulo errors during the first cast.
     Cleaning the main CTD connector apparently fixed the problem but the deep
     profile had to be truncated at 650 db post-cruise.  During the upcast at 
     station 16, broken strands were noticed at about 650m.  After the cast, 
     670m was cut off and the cable reterminated.

     PMC's Sea-Bird 9plus CTD s/n 09P13807-0439 (pressure s/n 59788) was used
     for all casts during this cruise, along with primary temp sensor s/n 2126 
     and primary cond sensor s/n 524, and secondary temp sensor s/n 4211 and 
     secondary cond sensor s/n 1467.  Also mounted on the A/D channels were a
     transmissometer(V2), fluorometer(V1), and backscatter(V0) sensor for 
     Pete Strutton.  No PAR.  No oxygen.

     The CTD was mounted in the TAO spare custom 24-bottle frame with TAO SBE 
     carousel pylon s/n 54.  The CTD data stream was passed through TAO 11plus
     V1 deck unit s/n 376 with factory settings.  Digitized data were sent
     to a Dell personal computer using Windows XP OS equipped with SBE's
     SEASOFT Windows acquisition software version 5.30b.  Calibrated 
     data were displayed in fixed listing and graphical form in real-time, as 
     well as stored in raw form onto hard disk.  Backups of the raw data were 
     made on a Sony thumb drive and DVD.   DVDs were returned to PMEL for 
     post-cruise processing.


     SALINITY SAMPLES:
   
     Salinity analysis was performed using Guildline Autosal 8400B salinometer 
     s/n 61.383, Ocean Scientific ACI2000, and IAPSO standard seawater batch 
     #P145 dated July 2004 and #P147 dated June 2006.  The bath temperature was 
     set to 27C after concluding that the Autosal room temperature could not be 
     maintained below 24.5C.  Eight samples are to be collected each cast.  Raw 
     data were archived along with CTD data on CD.  

     At PMEL, ACI2000 .dat files were ammended in Excel such that only 1 header
     line, 1 standard correction line, and 3 salinity lines per sample were
     included in the file.  Corrected salinity values were fixed to 4 decimal
     places and the file overwritten in the NT folder as a space delimited file.


     CONDUCTIVITY CALIBRATION:
   
     GP806S.CAL of secondary sensor data (te 4211, co 1467) was created at PMEL  
     and used to calibrate all stations 1-35.

     Final pressure and temperature calibrations were pre-cruise.  A viscous
     heating correction of -0.0006 C was applied to the temperature sensor.
    The drift correction for s/n 4211 was +0.00078 C.

     The results chosen were from an overall fit determined by CALCOS0:

     number of points used   159
     total number of points  181
     % of points used in fit 87.85
     fit standard deviation  0.003604
     fit bias               -0.007508372
     fit slope               1.0005433

     Slope and bias correction values were applied to CTD burst data using 
     a local version of CALMSTR.  Calibrated data were converted into NetCDF
     format using CLB_EPS on PC Pacific. Final calibrations were applied to 
     profile data and converted into NetCDF format using a local version of 
     CNV_EPS2P.  This version reads files that include 3 optical sensors for 
     Pete Strutton (no PAR) carried through as raw voltages.


     PROCESSING:

     All casts were reprocessed by KEM post-cruise to be sure of the format.  
     The following are the standard SEASOFT processing modules used to reduce 
     Sea-Bird CTD data:

     DATCNV converts raw data to engineering units and creates a bottle
     file if a Sea-Bird rosette sampler was used.  Both down and up casts
     are processed.

     BOTTLESUM averages the bottle data specified in the DATCNV output and 
     derives salinity, theta, and sigma-theta. Bottle data are used
     to calibrate the conductivity sensor post-cruise. 

     WILDEDIT makes two passes through the data in 100 scan bins.  The
     first pass flags points greater than 2 standard deviations; the
     seond pass removes points greater than 20 standard deviations from
     the mean with the flagged points excluded.  Data were kept within 100
     of the mean (i.e. all data).

     FILTER applies a low pass filter to pressure with a time constant of
     0.15 seconds.  In order to produce zero phase (no time shift) the
     filter is first run forward through the file and then run backwards
     through the file.

     CELLTM uses a recursive filter to remove conductivity cell thermal
     mass effects from the measured conductivity.  In areas with steep
     temperature gradients the thermal mass correction is on the order
     of 0.005 psu.  In other areas the correction is negligible.  The
     value used for the thermal anomaly amplitude (alpha) is 0.03.  The
     value used for the thermal anomaly time constant (1/beta) is 7.0.
 
     LOOPEDIT removes scans associated with pressure slowdowns and
     reversals.  If the CTD velocity is less than 0.25 m/s or the pressure
     is not greater than the previous maximum scan, the scan is omitted.

     BINAVG averages the data into 1 db bins.  Each bin is centered around
     a whole pressure value, e.g. the 1 db bin averages scans where pressure
     is between 0.5 db and 1.5 db.  There is no surface bin.

     DERIVE uses 1 db averaged pressure, temperature, and conductivity to
     compute salinity.

     TRANS converts the data file from binary to ASCII format.

     Program CNV_EPS2P applies post-cruise temperature corrections and
     conductivity calibration coefficients, as well as any offset to salinity,
     recomputes the derived variables in DERIVE, and converts the ASCII data
     files to netCDF format.  CNV_EPS2P skips bad records near the
     surface (typically the top 3 m) as well as any records containing
     -9.990e-29, and copies back raw data to the surface (0 db) within 15 db.
     Raw voltages for the optical sensors are not copied back but made zeros.
     Because the SBE module LOOPEDIT does not handle package slowdowns and
     reversals well in the thermocline where gradients are large, CNV_EPS2P
     removes raw data records where a sigma-theta inversion is greater than
     -0.01 kg/m3.  Data are linearly interpolated such that a record exists
     for every 1 db.  When data are copied back to the surface, the WOCE
     quality word is '8888'; when interpolated over greater than 2 db, the
     WOCE quality word is '6666'.  The WOCE quality word consists of a 1-digit
     flag for pressure, temperature (ITS-90), and salinity.

     Comparison with historical deep casts suggested an additional offset in
     salinity of -.005 for casts 1-18 along 165E and -.003 for casts 19-35 
     along 180.  This was done in local versions of CNV_EPS2P and CALMSTR.
     
     Four bottles were flagged bad: sample 105 for stations 13, 14, 22, and
     sample 104 for station 22.

     Final CTD and bottle files were moved to /home/plover/insitu2/DATA/hayes
     /gp806/ctd/ and /bot and included in the MySQL data management tables on
     January 5, 2007.
