Turnipseed CO Data Instructions

Investigator: Andrew Turnipseed, NCAR/ACD
turnip@ucar.edu
Date: 1/25/2012

Filename:  Turnipseed_RombasCOData.csv (comma delimited)

Data Interval:  10 min. averages
Initial Start time of file:  July 1, 2011, 0:00:00  (MST)
All CO data were taken from an inlet height of 3.5 m
Missing data = -9999

Columns:
Start_sec:	Beginning of 10 min. period  (seconds since July 1, 2011, 0:00:00 MST)
End_sec: 	End of 10 min. period  (seconds since July 1, 2011, 0:00:00 MST)
Mid_sec:	Midpoint of 10 min. period  (seconds since July 1, 2011, 0:00:00 MST)
Date:		MM/dd/YY, 
Time:		hh:mm:ss, Beginning of 10 min. period (MST)
Day of Year:	decimal day, Beginning of 10 min. period (MST)
CO:		carbon monoxide mixing ratio, ppbv


Instrumentation:
ThermoEnvironmental Gas Filter Correlation CO analyzer, Model 48 equipped
with a heated Pt catalytic converter. 	

Sampling Notes: The sampling cycle for the CO instrument involves a continuous cycle of 
measuring the atmospheric signal for 5 min., followed by 5 min. of scrubbed air (zero) using
a heated Pt-catalytic converter.  Each 5 min. cycle is averaged - then, the CO reported is 
obtained from the average of the (Signal cycle - the preceding zero) and 
(Signal Cycle - following zero).  The time tag was obtained from the center of the each
Signal Cycle.  As the valve controlling the sampling cycle was on its own timer - the differing
clocks caused the samples to not always be exactly 10 min. in duration and a bit irregular
with respect to the NIST time.  

Calibrations:  Calibrations using a NIST-traceable CO/air standard were conducted at 
3 different times: prior to ROMBAS, following ROMBAS, and during ROMBAS (8/11/11).  All
3 calibrations agreed to within 8% - so a single average calibration was applied to all
data.