RB-07-03
PNE 2007 Readme File

Ship:			NOAA research vessel Ronald H. Brown
Cruise Start:	        Bridgetown, Barbados, May 5, 2007
Cruise End:		Ft. Lauderdale, FL, May 29, 2007
Chief Scientist:	Rick Lumpkin
System Operator:	Randy Ramey
Expocode:               33RO20070505

Method:
Infrared absorption of dried gas.  For details of the system see: 
Measurement of fugacity of Carbon Dioxide in surface water and air using continuous 
sampling methods.  Wanninkhof and Thoning, 1993 in Marine Chemistry 44, 189-205, 
And:
Feely, R.A., R. Wanninkhof, H.B. Milburn, C.E. Cosca, M. Stapp, and P.P. Murphy, 
A new automated underway system for making high precision pCO2 measurements 
onboard research ships, Analytica Chim. Acta, 377, 185-191, 1998.

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

Sampling Cycle:
The system runs on an hourly cycle during which 3 standard gases, 3 air 
samples from the bow tower and 8 surface water samples (from the 
equilibrator head space) are analyzed on the following schedule:

Mins. after hour		Sample
4				Low Standard
8				Mid Standard
12				High Standard
16.5				Water
21				Water
25.5				Water
30				Water
34				Air
38				Air
42				Air
46.5				Water
51				Water
55.5				Water
60				Water

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 (289.06, 370.90, & 411.42 ppm) 
should be considered approximate (within 5 ppm).  While individual data points above 
411 or below 289 may not be accurate, the general trends should be indicative of the
seawater chemistry.
2.	The water flow to the equilibrator was shut down from May 10 at 23:20 to May 11 
at 0700 and from May 21 at 0920 to 1033.  All water values in this time period have been
removed.
3.	The SST readings froze from May 6 at 1842 to May 7 at 1000.  They were replaced
with the equilibrator temperature - 0.12 degrees C during this period.
4.	The ship's TSG began giving inaccurate readings on May 19 at approximately 1100.
All salinity values for this data set have been taken from the Micro TSG in the Hydro 
lab sink.
5.	On May 16 at 1030, the pump that draws air from the bow mast began to leak.  All 
air values after this time have been removed.  When the ship came into Ft. Lauderdale,
the pump's diaphragm was replaced, correcting the problem.


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