Partitioning the [Formula: see text] Flux Mediated by Droplets Released from Breaking Waves

The [Formula: see text] flux from spume droplets occurs in two steps. First, the initial droplet–air gas concentration gradient [Formula: see text] is immediately removed with no change in the droplet solubility. Then, the solubility changes with droplet temperature T and radius r evolution, but the flux maintains the condition [Formula: see text]. The gas content of a droplet can be determined by [Formula: see text] since the parameters T and r are known. Therefore, the net gas influx of a droplet depends on the values of T and r in its return to the sea. In the second step, the droplet temperature T evolves to an equilibrium temperature [Formula: see text], and the radius r is then reduced by evaporation at constant [Formula: see text]. For the droplet spectrum, a cut-off radius [Formula: see text] is used to separate short-lived ([Formula: see text], returning to the sea before [Formula: see text]) and long-lived [Formula: see text] conditions. The net influx is split into three contributions: the first ([Formula: see text]) is mediated by short-lived mechanisms, and the second and the third by long-lived ([Formula: see text]) mechanisms that are further separated into temperature-varying ([Formula: see text]) and radius-varying ([Formula: see text]) stages. The results show that, in the cases with large air–sea temperature differences, the first stage [Formula: see text] dominates the net gas input, but its importance decreases as the value of [Formula: see text] increases. The temperature-varying stage [Formula: see text] is dominant in cases with both large values of [Formula: see text] and large temperature differences, while the radius-varying stage [Formula: see text] increases as either the temperature difference decreases or as the value of [Formula: see text] increases.