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Parameter or Variable: pCO2 (fCO2) autonomous;
Abbreviation: fCO2_SW@SST;
Unit: uatm;
Observation type: Surface underway;
Measured or calculated: Measured;
Sampling instrument: Seawater pump;
Location of seawater intake: Bow;
Analyzing instrument: Infrared Analyzer: LI-COR model 6262;
Detailed sampling and analyzing information: Pierrot, D., Neill, C., Sullivan, K.,
Castle, R., Wanninkhof, R., Lüger, H., Johannessen, T., Olsen, A., Feely, R. A., &
Cosca, C. E. (2009). Recommendations for autonomous underway pCO2 measuring systems
and data-reduction routines. Deep Sea Research Part II: Topical Studies in Oceanography,
56(8-10), 512-522. https://doi.org/10.1016/j.dsr2.2008.12.005;
Equilibrator type: Spray head above dynamic pool, with thermal jacket;
Equilibrator volume: 0.95 L (0.4 L water, 0.55 L headspace);
Is the equilibrator vented or not: Vented;
Water flow rate: 1.5 - 2.0 L/min;
Gas flow rate: 70 - 150 ml/min;
How was temperature inside the equilibrator measured: Hart Scientific model 1523 digital
thermometer;
How was pressure inside the equilibrator measured: External Setra 270 connected to
the exit of the analyzer;
Drying method for gas: Gas stream passes through a thermoelectric condenser (~5 C)
and then through a Perma Pure (Nafion) dryer before reaching the analyzer (90% dry).;
SEA CO2 gas detector manufacturer: Licor, Inc;
SEA CO2 gas detector model: Licor 6262;
SEA CO2 gas detector resolution: Accuracy: +/- 2 uatm in fCO2_SW;
SEA CO2 gas detector uncertainty: Precision: +/- 0.01 uatm in fCO2_SW;
Standardization technique: The system runs a full cycle in approximately 7 hours.
The cycle starts with 4 standard gases, then measures three rounds of 6 atmopherice
samples followed by 50 surface water samples. Each new gas is flushed through the
Licor Analyzer for 2 minutes prior to a stop-flow measurement.;
Standardization frequency: Every 7 hours;
Standard gas manufacturer: Standard gases are supplied by NOAA Earth System Research
Laboratory, Global Monitoring Division, in Boulder, CO, and are directly traceable
to the WMO scale.;
Standard gas concentration: Std 1: CA06709, 284.75 ppm, owned by ESRL, used every
~ 3.5 hours. Std 2: CA02813, 363.24 ppm, owned by ESRL, used every ~3.5 hours. Std
3: CA07921, 423.57 ppm, owned by ESRL, used every ~3.5 hours. Std 4: CA07931, 545.88
ppm, owned by ESRL, used every ~3.5 hours. Std 5: 0.00 ppm, owned by AOML, used every
~20.0 hours.;
Standard gas uncertainty: 0.01 ppm;
Water vapor correction method: Details of the data reduction are described in Pierrot,
et.al. (2009).;
Temperature correction method: Details of the data reduction are described in Pierrot,
et.al. (2009).;
At what temperature was pCO2 reported: In situ sea surface temperature;
Uncertainty: 0.01C;
Quality flag convention: WOCE quality control flags are used: 2 = good value, 3 =
questionable value, 4 = bad value;
Method reference: Pierrot, D., Neill, C., Sullivan, K., Castle, R., Wanninkhof, R.,
Lüger, H., Johannessen, T., Olsen, A., Feely, R. A., & Cosca, C. E. (2009). Recommendations
for autonomous underway pCO2 measuring systems and data-reduction routines. Deep Sea
Research Part II: Topical Studies in Oceanography, 56(8-10), 512-522. https://doi.org/10.1016/j.dsr2.2008.12.005;
Researcher name: Denis Pierrot;
Researcher institution: NOAA/AOML
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