TAO 1999 Leg 1 Readme File

Ship:			NOAA research vessel Ronald H. Brown
Cruise Start:		Seattle, Wa, November 1, 1999
Cruise End:		San Diego, CA, December 2, 1999
Chief Scientist:	Andrew J. Shepherd
System Operator:	Esa Peltola
Expocode:               33RO19991102 

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 for Leg 1:

1. The system was shut down on 11/6 at 0050 GMT (310.032-310.753) for 
17 hours while the ship made a pick up in San Diego.
2. The system was shut down on 11/6 at 2020 GMT (310.854-314.083) for 
3-1/4 days while the ship was in Mexican waters.
3. The system was shut down on 12/2 at 2033 GMT (336.857) when the ship 
entered Mexican waters.  It was not turned on again during this leg.
4. On 2 occasions, low gas flow in the standard phases resulted in the 
incomplete flushing of the Licor sample cell.  The first of these 
went from 325.753 to 332.250 and the second from 333.6 to the end of 
the cruise.  In the first case, I averaged voltage response in the 
standard phases for the period from 324.336 to 325.711 (n=34) and 
replaced the bad values with the average values.  In the second 
case, I averaged voltage response in the standard phases for the 
period from 331.753 to 333.627 (n=46) and replaced the bad values 
with the averages.  Statistics for each of the averages are given 
below:

n			34		46
LoStdAvg		0.073247	0.073247
LoStdSD			0.001764	0.001837
MidStdAvg		0.491197	0.482420
MidStdSD		0.001668	0.003944
HiStdAvg		0.905697	0.896917
HiStdSD			0.002312	0.002658

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