EX1120 Readme


Class of Data:  Surface ocean carbon dioxide concentrations

Dataset Identifier:  EX1120

Expocode: 33KF20110618

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:  EX1120/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          CA07952          549.89           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.

     STD1 analyses were not used in the calibration due to lots of missing points.

     The atmospheric barometer was not working during this cruise.  The atmospheric 
     pressure was estimated using a constant offset (-7.87 +/- 0.47 hPa) from the LICOR 
     pressure.  The offset was calculated from data (n=22,430) collected over 7 cruises 
     between 2 January and 3 April, 2011. 

     The sea water flow rate was variable and no more than half its normal value (2 L/min).  
     The low sea water flow increased the change in temperature between the inlet (SST) 
     and the equilibrator.  The differences were large enough that the delta-temperarature 
     limits for flagging data as questionable (flag=3) were expanded from -0.5 and 1.0 
     degrees C to -1.5 and 3.0 to help differentiate within this data set.  To allow users 
     to better assess the appropriateness of the data for their purpose, the sea water flow 
     rate is appended to the data file containing the calculated fugacities.


Contact person for this dataset:  

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

Timestamp for dataset reduction:  12/4/11

Timestamp for most recent update of dataset:  12/4/11

Matlab version used for reduction: 1.10

Time period the dataset refers to:  6/18/2011 - 6/23/2011

Geographic area the dataset refers to:

   Day 1  - Bayonne, New Jersey (40.7 N / 74.1 W)
   Day 3  - Kings Wharf, Bermuda (32.3 N / 64.8 W)
   Day 4  - Kings Wharf, Bermuda (32.3 N / 64.8 W)
   Day 6  - Bayonne, New Jersey (40.7 N / 74.1 W)