


     GP1-04-KA
     NOAA Ship KA'IMIMOANA
     San Diego, CA - Manzanillo, Mexico
     March 26 - April 22, 2004

     Chief Scientist: Dave Zimmerman
     Survey Department: ST Randy Ramey, ST Shawn Gendron
     CTD Personnel: ST Randy Ramey, ST Shawn Gendron
     Final Processing: K. McTaggart


     ACQUISITION: 

     Forty-seven CTD profiles were collected during this cruise.  Twenty-one
     profiles were collected from 8N to 8S along 110W.  Twenty-six profiles
     were collected from 8S to 8N along 95W, and along the ship's trackline
     to 12N.  The majority of casts were to 1000m.  Seven casts were deep (>3000m)
     and one was to 500m (a test cast for the CTD).

     PMC's Sea-Bird 9plus CTD s/n 09P13807-0439 measuring pressure (s/n 
     59788), temperature sensors s/n 1710 (TAO) and s/n 4211 (PMC) and conduc-
     tivity sensors s/n 1697 (PMC) and s/n 1467 (TAO) were used for all casts.  

     The CTD was mounted in the TAO spare custom 24-bottle frame with TAO SBE 
     carousel pylon s/n 407.  The CTD data stream was passed through TAO 11plus
     deck unit s/n 376 with factory settings.  Digitized data were sent
     to a new Dell personal computer using Windows XP 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 a Sony thumb
     drive and DVD.   DVDs were 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 and 61.383, OSI ACI2000,
     and IAPSO standard seawater batch #P141 dated June 2002 and #P143 dated February
     2003.  Bath temperatures were set to 24 degrees Celsius.  From now on, only 8
     samples will be collected per cast instead of 12, and no samples will be collected
     from the half-degree stations between 3N-3S.  Raw data were archived
     on DVD along with CTD data.  

     Intermittent problems were resolved when the Autosals were plugged into clean
     power instead of utility power.  New heater lamps were installed in Autosal
     61.383.

     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.
     Two runs could not be used in calibrating the CTD owing to bad standardizations;
     stations 0071-0131 and 0201-0211 have no bottle data.


     POST-CRUISE CONDUCTIVITY CALIBRATIONS:
   
     GP104s.cal of primary sensor data (te 1710, co 1697) was created at PMEL and
     used to calibrate all stations 1-47.  

     Final pressure and temperature calibrations were pre-cruise.  A viscous
     heating correction of -0.0006 C was applied to temperature sensor s/n 1710
     but no historical data for a drift correction are available.

     For conductivity 1697, stations 1-47, CALCOS0 was used to determine the fit:

       [sta,slope,bias,newbotco,newctdco]=calcos0(stat,cond,pres,botc,2.8,1,47);
       number of points used   181
       total number of points  213
       % of points used in fit 84.98
       fit standard deviation  0.003135
       fit bias                0.0019262176
       min fit slope           0.99984963
       max fit slope           0.99984963

     Slope and bias correction values were applied to CTD burst 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 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_EPS1 applies post-cruise secondary 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_EPS1 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.
     Because the SBE module LOOPEDIT does not handle package slowdowns and
     reversals well in the thermocline where gradients are large, CNV_EPS1
     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.

     Compared to historical deep casts, GP104 deep casts were on the salty
     edge of the historical envelope.  No salinity offsets were applied.

     Final CTD and bottle files were moved to /home/plover/insitu2/DATA/hayes
     /gp104/ctd/ and /bot and included in the MySQL data management tables on 
     May 5, 2004.
