Tsunami Vents 2000 Readme File

Ship:			NOAA research vessel Ronald H. Brown
Cruise Start:		Seattle, Wa, March 17, 2000
Cruise End:		Newport, Or, March 22, 2000
Chief Scientist:	Scott Stalin
System Operator:	Bob Castle
Expocode:               33RO20000318

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. A new system (System 2.6, replacing System 2.5) was used on this cruise for the first time.  
Side-by-side tests in the lab show the average difference in computed concentration for the two 
systems to average 0.2723 ppm with a standard deviation of 0.43575 (n = 289). The main difference 
between the two systems is that an improved temperature control system for the Licor analyzer has 
been introduced in System 2.6.  For further details contact Bob Castle (see address at the end of this file).
2. Water values before March 18 at 1900 GMT were removed due to high variability in the readings.  
This was caused by air leaks in the water lines.
3. The system was down from 2130 GMT on March 18 to 0300 GMT on March 19 except for 1/2 hour while 
work was done on the plumbing connections.
4. The system was down from 2015 GMT to 2358 on March 20 for software modifications.
5. Data from 2045 GMT to 2400 on March 21 was discarded because system work corrupted the readings.
6. The system was down from 0430 to 0500 GMT on March 22 to replace a tube in the equilibrator.

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