Surface underway measurements of fugacity of carbon dioxide (fCO2), temperature, salinity and other variables collected during the R/V Thomas G. Thompson Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP) Section I06S cruise TN366 (EXPOCODE 325020190403) in the Southern and Indian Oceans from 2019-04-07 to 2019-05-14 (NCEI Accession 0208231)
PACKAGE DESCRIPTION: This dataset consists of Surface underway measurements of fugacity of carbon dioxide (fCO2), temperature, salinity and other variables collected during the R/V Thomas G. Thompson Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP) Section I06S cruise TN366 (EXPOCODE 325020190403) in the Southern and Indian Oceans from 2019-04-07 to 2019-05-14. The cruise began and ended in Cape Town, South Africa and collected data in the Southern and Indian Oceans. This effort was conducted in support of the Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP) and NOAA's Climate Program Office (CPO).
CITE AS: Alin, Simone R.; Collins, Andrew; Feely, Richard A.; Cosca, Catherine E. (2019). Surface underway measurements of fugacity of carbon dioxide (fCO2), temperature, salinity and other variables collected during the R/V Thomas G. Thompson Global Ocean Ship-Based Hydrographic Investigations Program (GO-SHIP) Section I06S cruise TN366 (EXPOCODE 325020190403) in the Southern and Indian Oceans from 2019-04-07 to 2019-05-14 (NCEI Accession 0208231). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/bbbk-s514. Accessed [date].
Surface underway;
TEMPORAL COVERAGE:
SPATIAL COVERAGE:
GEOGRAPHIC NAMES:
PLATFORMS:
RESEARCH PROJECT(S):
VARIABLES / PARAMETERS:
pCO2 (fCO2) autonomous | |
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Abbreviation: | fCO2_SW@SST_uatm, dfCO2_uatm |
Unit: | uatm |
Observation type: | Surface underway |
Measured or calculated: | Measured |
Calculation method and parameters: | Fugacity of CO2 is obtained by correcting the partial pressure of CO2 (pCO2) for non-ideality of the gas with respect to molecular interactions between CO2 and other gases in air. See Pierrot et al. for details on how the correction is made. |
Sampling instrument: | Seawater pump |
Location of seawater intake: | Bow |
Analyzing instrument: | General Oceanics 8050. PMEL system ID: C12/15034/157 |
Detailed sampling and analyzing information: | The sampling and analyzing methods of the Neill/General Oceanics Underway pCO2 systems are described in detail in: Pierrot, D., C. Neill, K. Sullivan, R. Castle, R. Wanninkhof, H. Lüger, T. Johannessen, A. Olsen, R.A. Feely, and C.E. Cosca (2009): Recommendations for autonomous underway pCO2 measuring systems and data-reduction routines. Deep-Sea Res. II, 56(8-10), 512-522, https://doi.org/10.1016/j.dsr2.2008.12.005. |
Equilibrator type: | Shower head |
Equilibrator volume: | ~0.5 L |
Is the equilibrator vented or not: | Vented |
Water flow rate: | 3 L/min |
Gas flow rate: | ~0.8 L/m |
How was temperature inside the equilibrator measured: | Hart Scientific model 1523 digital thermometer, serial number A71212, with an NIST traceable model 5610 thermistor probe, serial number B2C0403. Accurate to ± 0.01°C.. |
How was pressure inside the equilibrator measured: | Setra 239 differential pressure transducer, accurate to ± 0.15 hPa. The equilibrator was passively vented to a secondary equilibrator, and the Licor sample output was vented to the laboratory when CO2 measurements were made, thus equilibrator headspace pressure was assumed to be laboratory pressure. |
Drying method for gas: | From Pierrot et al.: Sample air is dried in a condenser that is cooled to 4-5 °C by a Peltier thermoelectric device. This partially dried air flushes a chamber that is vented and remains at ambient pressure. The dried air inside the chamber is used as the counter flow in the Nafion� tubing. A vacuum pump pulls the dried air from the chamber first through a fixed restrictor and then through the Nafion tubes, thus creating an absolute pressure and corresponding partial pressure gradient for water vapor across the membrane. When atmospheric air is measured, some of the partially dried air (80- 100 ml/min) is pushed through a Nafion tube, the analyzer and out a vent instead of flushing the chamber. The headspace gas, when being measured, is circulated in a closed loop through the analyzer at a rate similar to that of the atmospheric air (80-100 ml/min). It is dried first in the condenser, then in a Nafion tube prior to entering the analyzer and being returned to the equilibrator. Typically, the water mole fraction (xH2O) in the dried gas is about 2 parts per thousand (ppt), which corresponds to a dew point temperature of about -20 °C. The liquid water condensed out of the sample air streams is removed by peristaltic pumps into the vent equilibrator at intervals determined by the user. |
SEA CO2 gas detector manufacturer: | Licor, Inc |
SEA CO2 gas detector model: | Licor 7000, IRG4-0583 |
SEA CO2 gas detector resolution: | 0.2 µatm |
SEA CO2 gas detector uncertainty: | 0.3 µatm for equilibrator measurements, 0.2 µatm for atmospheric measurements |
Standardization technique: | The system runs a full cycle in approximately 6 hours. The cycle starts with 4 standard gases composed of a known quantity of CO2 in air, a gas composed of 100% ultra-high purity nitrogen, then measures 6 atmopheric samples followed by 60 surface water samples. The gas detector runs a zero and span routine twice daily, using the nitrogen and highest CO2 gas standard, respectively. Each new gas is flushed through the Licor Analyzer for 3 minutes prior to a stop-flow measurement. |
Standardization frequency: | Every three hours |
Standard gas manufacturer: | Standard gases are supplied by NOAAs Earth System Research Laboratory, Global Monitoring Division, in Boulder, CO, and are directly traceable to the WMO scale. |
Standard gas concentration: | LL122869 = 304.26, LL122858 = 493.83, LL122359 = 639.36, LL63969 = 872.6 |
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: | ± 0.01°C |
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: | Collins, A.U. |
Researcher institution: | Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration |
Sea Surface Temperature | |
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Abbreviation: | SST_C |
Unit: | Degrees Celsius |
Observation type: | Surface Underway |
Sampling instrument: | In-situ observation |
Analyzing instrument: | Seabird Electronics 45, maintained and calibrated yearly by ship personnel |
Uncertainty: | 0.0025°C |
Sea Surface Salinity | |
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Abbreviation: | SAL_permil |
Unit: | permil |
Observation type: | Surface Underway |
Sampling instrument: | Seabird Electronics 45, maintained and calibrated yearly by ship personnel |
Detailed sampling and analyzing information: | During the first seven days of data collection, the ship's salinity measurements were inaccurate. A new sensor was installed on 11-Apr-19. Data during these first seven days (4-Apr-19 to 11-Apr-19) were post corrected using a 2nd order polynomial regression using discrete measurements collected underway and analyzed on a Guildline Autosal salinometer. |
Uncertainty: | 0.005 PSU |
SUBMITTED BY: Andrew Collins (andrew.collins@noaa.gov)
SUBMISSION DATE: 2019-12-12