     EP1-90-MB 
     NOAA Ship Malcolm Baldrige
     Honolulu, Hawaii - Panama
     21 April - 22 May, 1990

     Chief Scientist: M. McPhaden
     Survey Department: Chief Hopkins, D. Sweeney, T. Lantry
     CTD Personnel: D. Sweeney, T. Lantry
     Final Processing: K. McTaggart


     ACQUISITION:

     A total of 30 CTD casts were done by the ship's survey personnel (CST
     Hopkins, ST Dennis Sweeney, and ST Tom Lantry), the majority of which 
     were to 1000 meters.  AMC's CTD (S/N 2043) and 12-bottle rosette with 
     10-liter bottles were used for all casts.  CTD 2043 did not have an 
     oxygen sensor, however oxygen samples were drawn and titrated by CST 
     Hopkins using a modified Winkler method.  Data returned to the lab 
     included a TK50 cartrige tape of the LOGGER disk files and salinity data,
     3 small 9-track backup tapes containing LOGGER disk files, 5 large 9-track
     backup tapes of CTD data taken at the time of each cast, 6 VCR backup 
     tapes of the audio signal during each cast, and printer listings with 
     pre-cruise calibrations applied.  The XYY' plotter used to monitor CTD 
     data quality in real time, and strip chart which is helpful in determining
     rosette misfires were apparently not used.  Documentation included the 
     ship's form of the CTD cast logs, A-sheets on water sampling, salinity and
     oxygen analyses, weather logs, and the dead-reckoning abstracts.  
  
     Because PMEL's CTD cast logs were not filled out at sea, these were
     compiled back at the lab.  The primary source of information were the 
     ship's CTD cast logs.  Deck unit P, T, C, and time of bottle stops were 
     transcribed from these.  The A-sheets provided Niskin bottle numbers and 
     positions on the rosette, nominal firing depths, and salinity and oxygen 
     sampling bottle numbers.  Water sample salinity and oxygen data came from
     survey summary listings attached to their cast logs.  CTD P, T, salinity
     (with precruise calibrations applied), and information on backup sequence
     came from the printer listings.  Cast header information came from the 
     bridge's weather logs.  Depths of the water column were rarely noted at 
     CTD stations.  The nearest depth recorded on the DRAs was corrected and 
     used where needed.  Also created at the lab were the header and .CAL files
     using EDT and CALDSK.

     Two autosals were contained aboard ship.  Samples of P112 standard
     water were used throughout the cruise to standardize the salinometers
     before and after each run.  The drift during each run was monitored and
     individual samples were corrected for this drift during each run by linear
     interpolation.
     
     CONDUCTIVITY CALIBRATIONS:

     A listing of the data with precruise calibrations applied was made
     using CALMSTR.  Plots of P, T, C, salinity, and cast number verses the
     difference in CTD and bottle conductivity were generated, as well as deep
     TS plots of CTD and bottle data (in this case, deep meant the 500 and 1000 
     meter bottles).  The differences in CTD and bottle salinities were noted
     and the .CAL was checked for typos, bad points, and misfires.  There were
     4 missing bottle salts from survey and no evidence of any misfires.  

     CTD pressure and temperature values were corrected using precruise
     calibration coefficients determined by NWRCC in December 1989.  

     2043    6  380
     -0.7603    .9987171  0.348780E-6  -0.3157158E-10   P DN  S/N 2043  DEC 89 
     -2.2141    .9935210  0.248593E-5  -0.2361966E-09   P UP  S/N 2043  DEC 89
     -0.0024   1.0000330  0.000000E-6   0.0000000E-10   T     S/N 2043  DEC 89
     -0.0124    .9988607  0.000000E-6   0.0000000E-10   C     S/N 2043  DEC 89
     
     Final calibrations for pressure and temperature remained the same as the
     pre-cruise. The new International Temperature Scale of 1990 (ITS-90) was 
     NOT applied to the temperature values of this data set. A new conductivity 
     calibration was determined in the lab using LINCAL which
     calculates a linear fit of bottle conductivity verses CTD conductivity,
     applies this fit, and throws out pairs of data whose difference is 2.8
     times the standard deviation.  It then recalculates the fit and iterates
     through the data until no values are thrown out.  In this case, 68 values
     were discarded from a total of 306 values in 10 repetitions.  The maximum
     residual was 0.0143 and the standard deviation was 0.0051.  The new 
     conductivity coefficients were A0:-.0219 and A1:0.9987329.  A new listing
     with this first-order correction applied was made using CALMSTR, and the
     same types of plots were generated.  No trends or offsets were evidenced
     in these plots.  Keep in mind that these are only 1000 meter casts and 
     that high variability in the surface layer is expected.

     After processing the data (see the following section) and deep CTD
     data was compared with historical data (fall EPOCS 1989), only one
     outstanding bottle salinity value was thrown out (1000 meter bottle from 
     cast 25).  Bottle files were generated into PMEL's EPIC format using 
     EPICBOMSTR.


     PROCESSING:

     CTD cast data was restored from the TK50 cartrige tape.  Casts 16
     and 21 however were empty files, and had to be restored from the small
     9-track magnetic tapes.  As has been the lab's experience in the past
     with AOML tapes, these were unreadable by our VAX system.  Fortunately,
     a computer specialist, Tiffany Vance, was able to read the tapes on
     a microVAX system (node Huey).  

     DPDNZ read the raw data files and calculated the fall rate every 
     60 scans.  This output was input into DLAGAVZ which creates a file of 
     1-meter averages.  DLAGAVZ lags and despikes the data, performs fall 
     rate editing, and applies pre-cruise calibrations, writing uncalibrated 
     conductivity to the file which is then used by EPCTD.  The minimum fall 
     rate allowable was 0.5 with a pressure interval of 1.2 meters. EPCTD 
     despikes the data, fills the data to one value every decibar, and applies
     final calibrations as specified in it's command file. The new conductivity
     calibration coefficients calculated in the lab were applied here.  EPCTD 
     also computes salinity, sigma-theta etc., adds meteorological header 
     information to the data file, and puts the data in PMEL's EPIC format.

     The EPIC formatted bottle and CTD data files were used to produce
     various plots for the final data report.  Among these, TS plots of the 
     entire water column were made for each cast.  These showed that casts 1, 
     4, 9, 14, 20, 25, 26, and 27 had surface spikes and needed to be despiked 
     manually.  A majority of the TS curves were jagged.  Cast 29 was the most
     obvious.  This was investigated by running REDDIC on the raw dpdn data
     (before editing) and plotting the problem area with no points thrown out.
     Then another plot was made of the problem area with bad points thrown out
     but the data still unaveraged.  A third plot was made of the good 1-meter
     averaged data, then a fourth after running EPCTD which by default checks
     the gradient on either side of a point and if it is less than that 
     allowable (in this case 0.025 for 0-200m), then that point is thrown out
     and a linearly interpolated value is put in its place.  3 major features
     in the problem area of cast 29 were editted out here.  Stan decided this
     gradient editting was necessary only in special cases and the default 
     should be false in EPCTD.COM.  So EPCTD was reran on all of the casts, and
     the data report reflects these final versions in all its plots.  (The lack
     of editting retained two spikes which had to be taken out manually.  These
     were cast 18 574 db and cast 23 198 db points.)  The
     original point in question of cast 29 was not discarded by EPCTD because
     the higher values of salinity existed over several meters.  This was seen
     by plotting the output of REDDIC; temperature and conductivity vs. depth.
     The jagged TS curves are due to the water properties varying so greatly
     with incremental changes in depth.
        
     The TS plots were also compared to historical data from the fall of 
     1989 data report.  This comparison showed excellent correlation for
     depths greater than 200 meters.

     end
