


     GP4-03-KA
     NOAA Ship KA'IMIMOANA
     Kwajalein, Marshall Islands - Honolulu, HI
     July 11 - August 7, 2003

     Chief Scientist: LCDR Chris Beaverson
     Survey Department: ST David Fischman
     CTD Personnel: ST David Fischman
     Final Processing: K. McTaggart


     ACQUISITION: 

     Fifty-seven CTD profiles were collected during this cruise.  Twenty-three
     profiles were collected from 8N to 8S along 165E; one test cast at 8S,
     170W; and 27 profiles were collected along 180 from 8S to 8N and along the
     ship's trackline from 8N to 12N.  Because the ship was ahead of schedule,
     5 extra 1000 m casts were done along the trackline enroute to the Big Eye
     mooring, at the request of NMFS, as well as one CTD at the Big Eye mooring
     site.  The majority of casts were to 1000m.  Five casts were deep (>3000m).
     Cast 0231 was aborted at 2033m, and cast 0261 was aborted at 386m, owing
     to a termination failure resulting in loss of communications.

     PMC's Sea-Bird 9plus CTD s/n 09P13807-0439 measuring pressure (s/n 
     59788), temperature sensors s/n 4211 (TAO) and s/n 2126 (PMC) and conduc-
     tivity sensors s/n 303 and s/n 1697 (both PMC) were used for all casts.

     The CTD was mounted in the TAO spare custom 24-bottle frame with SBE 
     carousel pylon s/n 54.  The CTD data stream was passed through 11plus
     deck unit s/n 376 with factory settings.  Digitized data were sent
     to a Dell personal computer using Windows 98 OS equipped with Sea-Bird's
     SEASOFT Windows acquisition software.  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 Zip disk
     and CD and the CD was returned to PMEL for post-cruise processing.


     SALINITIES:
   
     No duplicate samples were taken this cruise.  Salinity analysis was performed
     using Guildline Autosal 8400B salinometer s/n 61.667, OSI ACI2000 interface,
     and IAPSO standard seawater batch #P139 dated November, 2000 and #P141 dated
     June, 2002.  Bath temperature was set to 24 degrees Celsius.  Raw data were 
     archived on floppy disk and CD and returned to PMEL.

     No salinity samples were taken for aborted casts 0231, 0241 and 0261.

     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.


     POST-CRUISE CONDUCTIVITY CALIBRATIONS:
   
     GP403S.CAL of secondary sensor data (te 2126, co 1697) for stations 1-57 was 
     created at PMEL and used to calibrate station profiles 1-57, except station 35.
     Secondary data for station 35 were noisy owing to a broken pump, so primary data
     (te 4211, co 303) with pre-cruise calibrations were processed for this cast.

     Final pressure and temperature calibrations were pre-cruise.  A viscous
     heating correction of -0.0006 C was applied to temperature sensors s/n 2126
     and 4211 but no historical data for a drift correction are available for either
     sensor. 

     Secondary conductivity fit coefficients were determined using Matlab program
     CALCOS0 for conductivity s/n 1697.  An additional offset of -0.004 psu was
     applied to salinities in order to bring the deep profiles into their historical
     envelopes.

			number of points used   538
			total number of points  641
			% of points used in fit 83.93
			fit standard deviation  0.003865
			fit bias               -0.005309621
			min fit slope           1.000248
			max fit slope           1.000248

     Slope and bias correction values were applied to CTD burst data and converted
     directly into netCDF format using CALMSTR and CLB_SHIFT_EPS.

     A dozen bad salinities were flagged: cast 0071 105, cast 0081 104, cast 0101 104,
     cast 0131 108, cast 0141 102-109-110-111, cast 0151 104, cast 0221 102, cast 0361
     104, and cast 0551 101.  There are no bottle files in our database for stations
     0231, 0241, or 0261.  Flagged data are stored in gp403s_eps.clb.


     FINAL PROCESSING:

     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.

     ROSSUM averages the bottle data specified in the DATCNV output and 
     derives salinity, theta, sigma-t, and sigma-th. Bottle data are used
     to calibrate the CTD 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.

     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.
 
     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.

     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.

     DERIVE uses 1 db averaged pressure, temperature, and conductivity to
     compute salinity, theta, sigma-t, sigma-th, and dynamic height.

     TRANS converts the data file from binary to ASCII format.

     Program CNV_SHIFT_EPS2 applies post-cruise temperature corrections and
     conductivity calibration coefficients, as well as an offset to salinity,
     recomputes the derived variables in DERIVE, and converts the ASCII data
     files to netCDF format.  CNV_SHIFT_EPS2 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 10 db.
     Because the SBE module LOOPEDIT does not handle package slowdowns and
     reversals well in the thermocline where gradients are large, CNV_SHIFT_EPS2
     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 '888'; when interpolated over greater than 2 db, the
     WOCE quality word is '666'.  The WOCE quality word consists of a 1-digit
     flag for pressure, temperature (ITS-90), and salinity.

     Final CTD and bottle files were moved to /home/plover/insitu2/DATA/hayes
     /gp403/ctd/ and included in the MySQL data management tables on September
     17, 2003.
