For MAPCO2 Buoy Information See: SO-GasEx cruise report, Section 5.5.1 pgs 30-33

Parameter names, definitions and units:
pCO2 - Partial pressure of CO2 in seawater, units in µatm.
O2 - Dissolved oxygen, units in µmol kg-1.

Sampling and Analytical Methodology:
Data were collected by SAMI-CO2 sensors equipped with Aanderaa model 4175 oxygen optodes mounted at 5, 19, 34.5, 50, 75, 105 m depth. All sensors were calibrated in the lab prior to deployment. Blank solutions, used to detect drift in the CO2 measurements, were run every 3.5 days. The SAMI-CO2 sensor has an accuracy 1 ±1 µatm, the optodes have an accuracy of 5% (15 µmol kg-1 at an in situ O2 concentration of 300 µmol kg-1).

CO2 and O2 data were collected every half hour, and CO2 data were found to have good agreement with shipboard data after a 4 µatm was applied, and O2 data agreed well with discrete Winkler titrations (typically within 1 µmol kg-1). pH data was collected every hour, and interpolated to half hour intervals. The SAMI-pH sensor has an accuracy of 0.001 ± 0.0007 pH units.

The buoy was initially deployed on March 8, 2008 in a SF6/3He tracer patch, and was recovered on March 12, 2008 after it was observed to be riding too low in the water. The buoy was reconfigured, and redeployed on March 13, 2008. After the first deployment of the MapCO2 buoy the 105 m SAMI was moved up to 96 m. The ship was forced to leave the study area after the second buoy deployment due to a severe storm, and when it returned the tracer patch was dispersed. The buoy was recovered, a new tracer patch was put in place, and the buoy was deployed a third time on March 22, 2008. On March 26, 2008 the tracer patch split and the buoy, along with a small tracer patch, moved away from the main tracer patch, and was recovered on March 31, 2008.

Data Processing:
CO2 data were corrected for blank solutions, and missing data points due to the running of the blanks were replaced via linear interpolation. For quality control all data were compared to shipboard measurements when they were available (i.e. the ship was in the indicator patch).

Related files and references:
DeGrandpre, M.D., T.R. Hammar, S.P. Smith, and F.L. Sayles. 1995. In situ measurements of seawater pCO2. Limnol. Oceanogr. 40: 969-975. http://www.aadi.no/Aanderaa/Document%20Library/1/Data%20Sheets/Oxygen%20Optodes_3.pdf

MAPCO2_SAMI.csv