Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Supplemental Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

Location: SUSTAIN wind-wave Tank, University of Miami

See Supplemental files section for "Noble Gas Ratios of Saturation Anomalies" data.

Methodology:
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Noble gas ratios are measured using a Gas equilibator Inlet Mass Spectrometer (GEMS) according to Manning et al. (2016). O2/Ar ratios are measured using an Equilibator Inlet Mass Spectrometer (EIMS), similar to that of Cassar et al 2009 but with an equilibator system as in the GEMS. O2 concentrations are measured by an optode calibrated by Winkler. All of those data streams are combined to calculate noble gas concentrations.

Sampling and analytical procedures:

A full description of the sample collection and analysis is in Stanley et al., “Gas Fluxes and Steady State Saturation Anomalies at Very High Wind Speeds“ Submitted to JGR-Oceans in Dec. 2021 (Stanley et al., 2022). Relevant paragraphs from the methodology can be found in the Supplemental Files section of this dataset page.

See Supplemental files section for "Noble Gas Ratios of Saturation Anomalies" data.

Codes written in matlab were used to convert the raw mass spectrometer data into noble gas ratios. The ratios were then calibrated using measurements in air taken before and after each experiment. Similar calibrations were done for the O2/Ar ratios. Optode data was calibrated with Winkler Samples measured periodically through the experiment. As described above, the noble gas ratios, O2/Ar ratios and optode concentrations were combined to calculate noble gas calculations – all those calculations were done in Matlab. Then the discrete copper tube samples were used as a final calibration of the noble gas concentrations. 

BCO-DMO Data Manager Processing Notes:
* File ContinuousNobleGasData.txt imported into the BCO-DMO data system.
* Parameters (column names) renamed to comply with BCO-DMO naming conventions. See https://www.bco-dmo.org/page/bco-dmo-data-processing-conventions
* DateTime (UTC) column added in ISO 8601 format yyyy-mm-ddTHH:MM:SSZ.
* Sampling and Analytical methods summary saved as a pdf from the BCO-DMO metadata form so the formula can be read.  The methodology section on this page is plain-text only.
* NGRatiosofSatAnom.txt file extension changed to csv and attached as a Supplemental File.

NSF Abstract:

An exact description of gas exchange between the atmosphere and the ocean is not fully developed, yet it is a critical process for understanding climate change and ecosystem dynamics. This is particularly problematic when evaluating the important role of bubbles in air-sea gas exchange, especially in remote ocean locations where high winds and waves make direct measurements extremely difficult. This project seeks to provide needed fundamental, high wind/wave gas-exchange measurements by using a large, state-of-the-art, wind-wave tank. Here the PIs can apply their novel measurements of noble gases (neon, argon, krypton, and xenon) to calculate overall gas fluxes under precisely controlled conditions. This tank setting allows a systematic approach to define the physical and chemical parameters (temperature, salinity, pH, wind speed, turbulence, bubble size distribution, etc.) required to construct more accurate models without the great uncertainties inherent in making similar measurements from a ship in storm conditions. A significant outcome of this study, beyond improved understanding of air-sea gas exchange, could be greatly improved estimates of the critical ecological balance between photosynthesis and respiration. Current methods use carbon dioxide and oxygen dissolved in seawater as an indication of biological activity, but cannot distinguish between biological processes and atmospheric exchange, and estimates are especially inaccurate under high wind and wave conditions with strong bubble injection. This study will improve our ability to separate biological and physical processes in evaluation of dissolved gasses in seawater.

Also, this project will provide 15 female undergraduate students at Wellesley College with an exciting, on-site research experience using a state-of-the-art tank facility at the University of Miami, and results will be incorporated into general and advanced chemistry classes. The production of student-created, short format videos, and other public outreach activities will also be supported to disseminate information on the importance of marine gas exchange.

The study of gas exchange processes between the ocean and the atmosphere has been hindered by the lack of data required to define quantitative relationships that account for bubble processes under a variety of wind, wave, and temperature conditions. Current gas exchange models tend to be highly unreliable in their parameterization of bubble processes. In large part, this is due to the difficulty of making traditional measurements at sea in remote locations within well-defined conditions, especially with high winds and waves. By using the large SUSTAIN wind-wave tank (23 m x 6 m x 2 m), the researchers in this project plan to greatly advance our understanding of the effect of wind, wave, and temperature variability on gas transfer. The use of a recently developed, field-portable equilibrator mass spectrometer that allows nearly continuous measurements of noble gas ratios (Ne, Ar, Kr, and Xe) will result in these SUSTAIN tank experiments providing precisely characterized gas flux data under varying wind speeds from 10 to 40 m/s. In addition, an underwater shadowgraph system will image bubbles, allowing the researchers to quantify bubble size distributions, a key factor missing from bubble models. Current models use a greatly simplified, two size-class representation of bubbles; an approach that this research will re-evaluate in hopes of creating better parameterizations of the role of bubble size on gas flux, and consequently improved air-sea gas exchange models for oceanic and climatic applications.