Incorporation of Alternative Sensors in the SOCAT Database and Adjustments to Dataset Quality Control Flags Recommendations

Wanninkhof, R., D.C.E. Bakker, N. Bates, A. Olsen, T. Steinhoff and A.J. Sutton. 2013. Incorporation of Alternative Sensors in the SOCAT Database and Adjustments to Dataset Quality Control Flags. http://cdiac.ornl.gov/oceans/Recommendationnewsensors.pdf. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tennessee. doi: 10.3334/CDIAC/OTG.SOCAT_ADQCF With the advent of new sensors and platforms to measure surface water carbon dioxide (CO2) levels, the dataset quality control (QC) criteria are updated in the Surface Ocean CO2 Atlas (SOCAT) to accommodate surface water fugacity of CO2 (fCO2w) data from these sensors. The current dataset QC flags and their rationale are described. The new sensors and platforms are briefly presented. Some changes in the criteria for assigning dataset QC flags and a new data quality flag are introduced. The term “dataset QC flag” replaces “cruise QC flag” to reflect the alternate platforms that are included in SOCAT. All dataset QC flags will incorporate a specified accuracy of the data. For equilibrator based systems the criteria for equilibrator pressure measurements are relaxed as they are unnecessary stringent for the accuracy of fCO2 in surface seawater. The acceptable comparison with other in situ data, defined as a high quality cross-over, will meet specific criteria of maximum distance, differences in fCO2w and sea surface temperature (SST) between two datasets. The scientist submitting the dataset will enter a preliminary dataset flag. Platform type including alternative platforms, such as buoys and selfpropelled surface vehicles, will be provided in the metadata and will be available as a selectable option in the Live Access Server (LAS) for SOCAT. These updates facilitate better separation of 1 Since there is no absolute standard for pCO2 in seawater, the term accuracy throughout refers to agreement with accepted values obtained from conventional state-of-the art systems such as described in Pierrot et al. (2009).

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