GP8-03-KA NOAA Ship KA'IMIMOANA Kwajalein, Marshall Islands - Honolulu, HI November 17 - December 13, 2003 Chief Scientist: Linda Stratton Survey Department: ST Lillian Stuart CTD Personnel: ST Lillian Stuart, Karen Taylor Final Processing: K. McTaggart ACQUISITION: Fifty CTD profiles were collected during this cruise. Twenty-three profiles were collected from 8N to 8S along 165E. Twenty-seven profiles were collected from 8S to 8N along 180, and along the ship's trackline to 12N. The majority of casts were to 1000m. Four casts were deep (>2300m) and one was to 1600m. 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 1537 (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 88. 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, CD, and DVD. CD and DVD 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, OSI ACI2000 interface, and IAPSO standard seawater batch #P141 dated June, 2002. Bath temperature was set to 24 degrees Celsius. Raw data were archived on the CTD data CD and returned to PMEL. One run containing station 6 and 7 samples had a bad standardization. Samples from these two stations were not used in calibrations. 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: GP803s.cal2 of secondary sensor data (te 2126, co 1537) was created at PMEL and used to calibrate stations 1-50. Primary conductivity sensor 303 continues to read low by 0.02 mS/cm in the top 200m (owing to bad or outdated or mistyped coefficients) and was not chosen for final calibration. 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 s/n 4211 but no historical data for a drift correction are available for either sensor. For conductivity 1537, stations 1-50, CALCOS0 was used to determine the best fit: [sta,slope,bias,newbotco,newctdco]=calcos0(stat,cond,pres,botc,2.8,1,50); number of points used 459 total number of points 567 % of points used in fit 80.95 fit standard deviation 0.002943 fit bias -0.015357053 min fit slope 1.0004159 max fit slope 1.0004159 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_EPS2 applies post-cruise secondary 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_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_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. Bad salinities were flagged in *_eps.clb files and omitted from the .nc bottle data files: station 0031 sample 105 station 0131 sample 109 station 0211 sample 104 station 0381 sample 104 station 0461 sample 108 station 0471 sample 109 station 0481 sample 109 Final CTD and bottle files were moved to /home/plover/insitu2/DATA/hayes /gp803/ctd/ and included in the MySQL data management tables on January 26, 2004.