EX1141 Readme


Class of Data:  Surface ocean carbon dioxide concentrations

Dataset Identifier:  EX1141

Expocode: 33KF20111110

Statement of how to cite dataset:

     For information on dataset citation and more, please see Master Readme File.
     Explorer website: http://www.aoml.noaa.gov/ocd/gcc/explorer_introduction.php

Measurement platform identifier:  EX1141/Explorer

Data quality issues:


     Standard Gases and Reference Gas:  The three standard gases come from CMDL
     in Boulder and are directly traceable to the WMO scale.  The zero gas
     is a non-calibrated gas from a commercial company.  Any value outside the
     range of the standards should be considered approximate (5 ppm).
     While individual data points above 550 or below 300 may less accurate,
     the general trends should be indicative of the seawater chemistry.  
     The standards used on the cruise are:

      STANDARD        TANK #       CONCENTRATION       VENDOR
        STD1                            0.00         Commercial
        STD2         CA05988          593.64           CMDL
        STD3         CA02040          319.82           CMDL  
        STD4         CA02030          377.14           CMDL        

     Units:  All xCO2 values are reported in parts per million (ppm) and fCO2
     values are reported in microatmospheres (uatm) assuming 100% humidity at the
     equilibrator temperature.

     The data acquistion started approximately a day after the ship departed NJ.  The
     serial connections for GPS, SST, TSG and atmospheric pressure were not 
     established.  These data were merged from ship's files based on the computer date
     and time.

     The sea water flow and salinity were more variable than usual for the first 1.5 days.
     Rougher seas might have been putting more air into the sea water pump than the 
     debubbler in front of the TSG could handle.  For the first half a day, the variability
     in water flow was greater and the measured sea water temperatures and CO2 were more 
     variable too.  These conditions often indicate fresh water rinses of the sea water
     manifold triggered by loss of prime on the pump.  The affected CO2 data were
     deleted.

     While the ship was in St. Maarten, the power to the chiller and vent fan were lost, 
     which caused the temperature in the LICOR analyzer to be higher than its upper limit.
     The reponse of the analyzer decreased substantially but remained constant.  When
     the mole fractions of CO2 in the sample analyses were recalculated based on the
     bracketing standard, the results were consistent with previous data.  The LICOR
     temperature and response plus the chiller temperature all remained outside their 
     normal ranges over the last 5.5 days of this cruise.  The atmospheric gas flow
     rate was just below its lower limit for the later part of the cruise.  The quality
     flags reflect these non-standard conditions.

Contact person for this dataset:  

     Kevin Sullivan
     (305)361-4382
     Kevin.Sullivan@noaa.gov

Timestamp for dataset reduction:  1/26/12

Timestamp for most recent update of dataset:  1/26/12

Matlab version used for reduction: 1.10

Time period the dataset refers to:  11/10/2011 - 11/20/2011

Geographic area the dataset refers to:

   Day 1  - Bayonne, New Jersey (40.7 N / 74.1 W)
   Day 5  - Philipsburg, St.Maarten (18 N / 63 W)
   Day 6  - Charlotte Amalie, St.Thomas (18.3 N / 64.9 W)
   Day 7  - San Juan, Puerto Rico (18.5 N / 66.1 W)
   Day 8  - Labadee, Haiti (19.8 N / 72.2 W)
   Day 11 - Bayonne, New Jersey (40.7 N / 74.1 W)