


     GP8-02-KA
     NOAA Ship Ka'imimoana
     Kwajalein, Marshall Islands - Honolulu, HI
     November 1-25, 2002

     Chief Scientist: Mr. Dave Zimmerman
     Survey Department: Ens. Sarah Dunsford
     CTD Personnel: Ens. Sarah Dunsford, Mindy Kelley
     Final Processing: K. McTaggart


     ACQUISITION: 

     ST Jason Poe was on leave this cruise.  Augmenting ST Randy Ramey was
     called away at the last minute to a family emergency.  Ensign Dunsford
     volunteered to do CTDs and salinities with the help of the barnacle
     scientist, Mindy Kelley.

     Forty-four CTD profiles were collected during this cruise from 8N to 8S
     along 165E, 8S to 5N along 180, 5N to 8N along 170W, and 9N to 12N along
     the ship's trackline to Honolulu.  The majority of casts were to 1000m,
     3 were deep.  Cast 0301 was acquired in two pieces, down and up.

     PMEL's Sea-Bird 9plus CTD s/n 09P3450-0209 measuring pressure (s/n 
     53586), PMEL's temperature sensors (s/n 1460, 4211) and conductivity
     conductivity sensors (s/n 197, 354) were used for all casts.

     The CTD was mounted in the TAO spare custom 24-bottle frame with a new
     Sea-Bird carousel pylon s/n 407.  The CTD data stream was passed through
     11plus deck units, 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:

     Only 8 samples were per cast.  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.  Laboratory operating temperature was assumed to be between
     23-24 degrees Celsius.  Raw data were archived on floppy disk and returned
     to PMEL on CD separate from the data package.

     The majority of salinities collected along the 165E line were analyzed
     during the transit from 165E to 180.  Rough seas and work on the ship's air
     conditioning postponed the analysis of the rest of the salinities until
     the ship reached port in Honolulu.  Mindy Kelley ran the salinities in port
     during the first week of December.

     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:

     GP802S.CAL of secondary sensor data was created at PMEL.  Primary data were
     not used because the residual conductivity scatter between CTD and bottles
     was greater.  

     Final pressure and temperature calibrations were pre-cruise.  A viscous
     heating correction of -0.0006 C was applied to temperature sensor s/n 1460
     but no historical data for a drift correction are available for this sensor
     (on loan from the PMEL instrument pool).

     Conductivity fit coefficients were determined using Matlab program
     CALCOS1.

                         number of points used   245
                         total number of points  320
                         % of points used in fit 76.56
                         fit standard deviation  0.002749
                         fit bias                0.0011799944
                         min fit slope           0.99998297
                         max fit slope           1.0000584

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

     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 9.0.
 
     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_EPS applies post-cruise temperature corrections and
     conductivity calibration coefficients, recomputes the derived variables 
     in DERIVE, and converts the ASCII data files to netCDF format.  CNV_EPS
     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_EPS 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.

     Cast 0231 was missing 0-11 dbar and cast 0321 was missing 0-36 dbar, so
     their upcasts were used instead of their downcasts.

     Program CALMSTR applies post-cruise temperature corrections and 
     conductivity calibration coefficients and recomputes the derived variables
     in ROSSUM.  CLB_EPS converts the ASCII bottle data file into individual
     cast netCDF data files (excluding those flagged as bad).  Bad bottle data
     included cast 0011 sample 2, 0021 sample 12, 0121 sample 10, 0141 sample  1,
     0151 sample 6 and 7, 0281 sample 2, 0301 sample 1, and 0361 sample 3.

     Final CTD and bottle files were moved to /home/plover/insitu2/DATA/hayes
     /gp802/ctd/ and included in the MySQL data management tables on December
     20, 2002.
