RB-09-03 NTAS Readme File
  
Ship:                   NOAA research vessel Ronald H. Brown 
Cruise Start:           Charleston, SC, June 18, 2009 
Cruise End:             Bridgetown, Barbados, July 4, 2009 
Chief Scientists:       Al Plueddemann 
System Operator:        Jonathan Shannahoff  

Method: 
The system was built by General Oceanics (GO) and is described in  
Pierrot, et al. (2009).

The three standard gases come from CMDL in Boulder and are directly 
traceable to the WMO scale.  

Sampling Cycle: 
The system runs on an cycle during which 4 standard gases, 5 air  
samples from the bow tower and 50 surface water samples (from the  
equilibrator head space) are analyzed on the following schedule:   

1. Zero and span of Licor 
2. Four standard gases 
3. Five air samples 
4. Fifty equilibrator headspace gas samples 
5. Repeat steps 2 - 4 nine more times 
6. Restart from step 1  

Standards:  CA6709: 284.75 ppm, CA2813: 363.24 ppm, CA9721: 423.57 ppm, 
CA7931: 545.88 ppm.  

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.  

Notes:
1. Any values outside the range of the standards (284.75 to 545.88 
ppm) have been flagged as 3 and should be considered  approximate 
(within 5 ppm).  While individual data points above 545 or below 
285 may not be accurate, the general trends should be indicative 
of the seawater chemistry. 

2. Salinity readings from the ship's TSG were bad.  Readings from the
Seabird Micro TSG connected to the analytical system were used instead. 

3. An offset of 2.55 minutes was applied to SST data from the ship's 
computer system. 

4. There were 2 prolonged data interruptions.  The first occurred on 
June 19 at 03:06 and lasted until 14:16.  The second started on June 21
at 16:31 and ended on June 23 at 03:16. 

5. When the system came back on after the first data interruption, 
the GPS was not working.  It did not restart until June 23 at 14:35.
Positions during this time period were merged in from the ship's 
independent GPS data.  

For questions or comments contact: 
Bob Castle 
4301 Rickenbacker Causeway 
Miami, FL 33149 
305-361-4418 
robert.castle@noaa.gov

Pierrot, D., C. Neil, K. Sullivan, R. Castle, R. Wanninkhof, H. Lueger, 
T. Johannson, A. Olsen, R. A. Feely, and C. E. Cosca (2009),
Recommendations for autonomous underway pCO2 measuring systems 
and data reduction routines, Deep-Sea Res II, 56, 512-522.