Gasaustausch - Entwicklung und Ergebnis eines schnellen Massenbilanzverfahrens zur Messung der Austauschparameter

In this thesis a novel, fast and highly accurate technique was developed for measuring the transfer velocity of gases across the air-water interface. The method is based on a simultaneous measurement of concentrations of gas tracers, both on the air and water side. It is possible to induce very high mass fluxes across the interface by increasing the water sided concentration. This leads to a significant increase in the air sided concentration of the tracer, which can be measured within a couple of minutes. By conducting measurements in this scheme, transfer velocities are recovered 10 to 100 times faster than would be possible by measuring the water sided concentration alone. Due to this significant reduction in measurement time, the novel technique makes it possible to conduct several experiments directly one after the other. For the first time was it possible to carry out a series of measurements in one day. The relative accuracy of measuring transfer velocities was better than 1%, which made it possible to determine the Schmidt number exponent precisely. The transition of the Schmidt number exponent from a flat to a rough water surface could be assessed for the first time. This allowed for a parametrization with the facet model. With respect to wind speed dependence a surprising result was achieved: The Schmidt number exponent transitions much slower than previously expected.