Location: SUSTAIN wind-wave Tank, University of Miami

See Supplemental files "Experimental Conditions in SUSTAIN wind wave tank" which contain the same experiment numbers as this DiscreteNobleGasData dataset.

Methodology:

The noble gas concentrations (He, Ne, Ar, Kr and Xe) were measured at the Isotope Geochemistry facility at WHOI according to the method of Stanley et al. 2009 but with isotope dilution method for Kr and Xe, as in Jenkins et al. 2019. The copper tube samples were collected at the SUSTAIN tank at the start or end of each experiment and then shipped to WHOI for analysis. 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). Temperature was measured by an optode and salinity was interpolated from discrete samples collected by salinity and measured at the University of Miami.

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. Here is the relevant paragraph about discrete noble gas measurements from that paper:

At the end of every experiment, and at the beginning of approximately half the experiments (the experiments conducted with U_10 = 20, 30, 40 and 50 m s-1 and the invasion/evasion experiments), samples for discrete noble gas analysis were collected in copper tubes (Jenkins et al., 2019; Loose et al., 2016). The samples were drawn from the tank through pre-soaked tygon tubing into 1 m of 5/8” diameter copper tubing, bubbles were removed by rapping, and at least 1 L of water was allowed to flow through the tube. Flow was temporarily stopped by clips and then the ends of the copper tube were cold-welded (Young and Lupton, 1983), producing two gas-tight samples of ~45 g each per time-point, though typically only one sample was analyzed. Samples were shipped to the Isotope Geochemistry Facility at WHOI where the gases were first extracted from the sealed copper tube into 30 mL aluminosilicate glass ampoules using an evacuated noble gas extraction line (Jenkins et al., 2019) and then analyzed for He, Ne, Ar, Kr and Xe on a quadrupole mass spectrometer by first being separated cryogenically and then using ion beam manometry spectrometry for He, Ne and Ar, and isotope dilution for Kr and Xe (given the smaller abundances of Kr and Xe, isotope dilution is required for better precision and accuracy) (Jenkins et al., 2019; Stanley et al., 2009a). Precison of the system, based on measurements of duplicate samples, is 0.1% for He, Ne, Ar, Kr and 0.2% for Xe.

Temperature was interpolated from in situ measurements of temperature made by an Anderra optode located next to the in situ pump that brought water to the copper tubes. Salinity measurements were made at the beginning and end of most experiments and then interpolated to the time of noble gas data collection to obtain an appropriate salinity. The salinity in the SUSTAIN tank changed slowly for the most part since typically it was a closed system and thus evaporation was the only cause for change. However, at certain points within the experiment, new water was added to the tank and at those times, salinity samples were also taken. Thus the salinity data is usually smoothly changing but with some jumps.