Preliminary results of the SOPRAN seawater gas exchange experiment in the Heidelberg Aeolotron

In November of 2014, air-sea gas exchange measurements using natural seawater taken from the North Atlantic were performed at the large annular wind-wave tank in Heidelberg, the Aeolotron, within the BMBF project SOPRAN (Surface Ocean Processes in the Anthropocene). Gas exchange experiments with of a large number of trace gases and volatile chemical species covering a wide range of solubility and diffusivity were conducted. Eleven different wind speeds, ranging from 1.5 to over 20 m/s, were used. Additionally, at three different wind speed conditions, a bubble generator was used to simulate the effects of strongly breaking waves with bubble entrainment. Measured gas transfer velocities are shown with special focus on the transfer velocities of gases with low solubilities, for which the transport process is water-side controlled. In addition, the dependency of the transfer velocities on the Schmidt number exponent is shown.