GU0801 Readme

Class of Data:  Surface ocean carbon dioxide concentrations

Dataset Identifer:  GU0801

Expocode: 33GG20080403

Statement of how to cite dataset:

     Gordon Gunter website: http://www.aoml.noaa.gov/ocd/gcc/rvgunter_introduction.php

     For more information on dataset citation and for a full description of the  
     instrumentation and procedures, see the Master Readme file accessible
     thru the Master Readme link located in the left navigation bar of the
     R/V Gordon Gunter web pages.
 
Measurement platform identifier:  R/V Gordon Gunter

Data quality issues:

     The data reduction for this dataset was done using pCO2 Sys v1.0.

     The LICOR had a faulty pressure transducer.  The Peq was estimated from the
     Peq-Patm difference during the GU0802_Leg2 cruise.  The average difference
     was Peq-Patm = -1.26 +/- 0.33 mbar calculated on approximately 11,000 samples.
     That difference was applied to the LICOR pressure (cell press).

     TSG data was not available before April 19, 2008 (JDay 110).  The SST was
     estimated from the Teq-Tin values obtained during the GU0802_leg2 cruise.
     The average difference was Teq-Tin = -0.18 +/- 0.15 mbar calculated on
     approximately 11,000 samples.  The Salinity was fixed to 36.2, which is
     a value representative of the region as a whole, although some areas
     above latitude 29 will differ substantially from that value.

     Standard Gases and Reference Gas:  The three standard gases come from Scott-Marrin, Inc.,
     and are calibrated with primary standards that are directly traceable to the WMO scale.  
     The zero gas is a non-calibrated ultra-high purity gas from a commercial company.  Any 
     value outside the range of the standards should be considered approximate (5 ppm).
     While individual data points above 450 or below 245 may be 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              ja 2280          248.73       Scott-Marrin, Inc.
           STD3              ja 2292          372.88       Scott-Marrin, Inc.  
           STD4              ja 2261          450.59       Scott-Marrin, Inc.                 

                                       
     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.

Ship Information:

     NOAA Research Vessel Gordon Gunter website:  http://www.moc.noaa.gov/gu/index.html

Scientists responsible for technical quality of this dataset:

     Rik Wanninkhof
     (305)361-4379
     Rik.Wanninkhof@noaa.gov 

     Denis Pierrot
     (305)361-4441
     Denis.Pierrot@noaa.gov

Timestamp for dataset reduction:  09/20/08

Timestamp for most recent update of dataset:  9/20/08

Time period the dataset refers to:  4/03/2008 - 4/12/2008

Geographic area the dataset refers to:

     Gulf of Mexico