The Collaborative O-Buoy Project: O-Buoy Deployment Atmospheric CO2
Contact: Patricia Matrai, pmatrai@bigelow.org, 202-747-3255

Data files are named by year and contains all of the available records for that year.  The data files are comprised of atmospheric CO2 observations with following columns [units].  The file format and units are described at http://www.unidata.ucar.edu/software/idv/docs/userguide/data/TextPointData.html

Final data have the following columns headers:
Time[fmt="yyyy-MM-dd HH:mm:ss z"],Latitude[unit="deg"],Longitude[unit="deg"],AirCO2[unit="micromole/mole"]

Level1 data have the following column headers:
Time[fmt="yyyy-MM-dd HH:mm:ss z"],Latitude[unit="deg"],Longitude[unit="deg"],CanTemp[unit="degC"],MeasTemp[unit="degC"],AtmPres[unit="mbar"],xCO2[unit="micromole/mole"]

Abbreviations:
AtmPres - atmospheric pressure
AirCO2 - final CO2 concentration
xCO2 - L1 CO2 concentration

The following buoy deployments have final CO2 data posted on ACADIS:
O-Buoy1 2009-2010
O-Buoy2 2010-2011 (Data from 2010-11 through 2011-03 are limited due to buoy power issues)
O-Buoy3 2010 (2011 data are unavailable due to a malfunctioning sensor)
O-Buoy4 2011-2012 (2010 data are unavailable due to malfunctioning sensor)
O-Buoy5 2011-2012
O-Buoy6 2012
O-Buoy7 - No CO2 data are available due to connection problems
O-Buoy8 2012 (2013 data are unavailable due to death of instrument sampling pump in 2012-10)
O-Buoy9 - No CO2 data are available due to instrument failure.
O-Buoy10 2013-2014



All other data are unfiltered, level 1 data.  Final data will be fully populated and deposited at the end of each deployment.

CO2 mixing ratios for level 1 data without calibration coefficients will be reported as NaN.  These values will be corrected during the deployment or during the assembly of final data.

Data have some time periods masked according to list in "buoy-mask.csv" which is available by request.   In that file, "what" refers the instrumentation to be masked where "any" (or "all"), "co2", "gps", "met", "ozone", etc. t0 and t1 mark the start and end points of the masked periods.


OB4 2011-2012 CO2 data specific notes:
The instrument operated throughout the entire deployment (September 6 2011 – August 25 2012).
There were several issues that complicated data processing and application of trustworthy calibrations.
1. In the autumn when battery voltages were low the valves that delivered the standard gases did not function. When the buoy switched to the lithium batteries this issue was resolved.
2. There were time periods when the standard gas flow rates were diminished and it appears that the analytical cell may not have been fully flushed. Those data were eliminated.
3. Two standards were used (378.2 and 403.2 ppm) but the lower standard was depleted before the end of the deployment. 
4. Aside from the temperature and pressure dependencies of the instrument, there was some long term drift in the absolute zero (~2ppm) and the absolute response (~5ppm). All calculations were made based on the assumption that the higher standard was stable to the end.

O10 2013-2014 CO2 data specific notes:
 The sample pump for the OB10 CO2 system failed on 3/19/2014 and then ran again for a little while starting on 4/7/2014. Some data points during the winter were too low and have been eliminated.

readme version: 2014-12-30