@article {mesarchaki2015, title = {Measuring air{\textendash}sea gas-exchange velocities in a large-scale annular wind{\textendash}wave tank}, journal = {Ocean Sci.}, volume = {11}, year = {2015}, pages = {121--138}, doi = {10.5194/os-11-121-2015}, author = {Evridiki Mesarchaki and Christine Kr{\"a}uter and Kerstin Ellen Krall and Maximilian Bopp and F. Helleis and Jonathan Williams and Bernd J{\"a}hne} } @phdthesis {kraeuter2015, title = {Visualization of air-water gas exchange}, volume = {Dissertation}, year = {2015}, publisher = {Institut f{\"u}r Umweltphysik, Fakult{\"a}t f{\"u}r Physik und Astronomie, Univ.\ Heidelberg}, doi = {10.11588/heidok.00018209}, author = {Christine Kr{\"a}uter} } @article {kraeuter2014, title = {High resolution 2-D fluorescence imaging of the mass boundary layer thickness at free water surfaces}, journal = {J. Europ. Opt. Soc. Rap. Public.}, volume = {9}, year = {2014}, pages = {14016}, doi = {10.2971/jeos.2014.14016}, author = {Christine Kr{\"a}uter and Darya Trofimova and Daniel Kiefhaber and Nils Krah and Bernd J{\"a}hne} } @conference {kraeuter2014a, title = {High-resolution 2-D fluorescence imaging of gas transfer at a free water surface}, booktitle = {Ocean Science Meeting, 23--28. 02. 2014, Honolulu Hawaii}, year = {2014}, abstract = {A novel 2-D fluorescence imaging technique has been developed to visualize gas exchange between air and water using ammonia as a tracer. Fluorescence is stimulated by high-power LEDs and is observed from above with a low-noise, high-resolution and high-speed camera. The invasion of ammonia into water leads to an increase in pH (from a starting value of 4), which is visualized with a fluorescent dye. The flux of ammonia can be controlled by controlling its air-side concentration. A higher flux leads to an increase of the thickness of the layer, from which fluorescent light is emitted (pH > 7). In this way, a varying fraction of the thickness of the aqueous mass boundary layer is imaged. In addition to the fluorescence measurement, we conducted collocated and simultaneous thermography and wave imaging measurements. With this data set, it is possible to compare heat and gas transfer and to investigate the effect of waves on both transfer processes. First results will be presented.}, doi = {10.5281/zenodo.12330}, author = {Christine Kr{\"a}uter and Darya Trofimova and Leila Nagel and Bernd J{\"a}hne} } @article {mesarchaki2014a, title = {Measuring air-sea gas exchange velocities in a large scale annular wind-wave tank}, journal = {Ocean Sci. Discuss.}, volume = {11}, year = {2014}, pages = {1643--1689}, doi = {10.5194/osd-11-1643-2014}, author = {Evridiki Mesarchaki and Christine Kr{\"a}uter and Kerstin Ellen Krall and Maximilian Bopp and F. Helleis and Jonathan Williams and Bernd J{\"a}hne} } @conference {kraeuter2012, title = {Partitioning of the Trasfer Resistance between Air and Water}, booktitle = {SOLAS Open Science Conference, Washington State, USA}, year = {2012}, doi = {10.5281/zenodo.12328}, author = {Christine Kr{\"a}uter and Kerstin E. Richter and Evridiki Mesarchaki and Roland Rocholz and Jonathan Williams and Bernd J{\"a}hne} } @mastersthesis {kraeuter2011a, title = {Aufteilung des Transferwiderstands zwischen Luft und Wasser beim Austausch fl{\"u}chtiger Substanzen mittlerer L{\"o}slichkeit zwischen Ozean und Atmosph{\"a}re}, year = {2011}, school = {Institut f{\"u}r Umweltphysik, Fakult{\"a}t f{\"u}r Physik und Astronomie, Univ.\ Heidelberg}, abstract = {The main focus of this thesis is the investigation of the air-water exchange of volatile tracers of medium solubility. The transfer resistances of tracers with a broad spectrum of solubilities were measured in experiments at the Aeolotron wind-wave facility. The dependence of transfer resistances on friction velocity and mean square slope is studied for both clean water and water with an added surfactant. It becomes clear that neither friction velocity nor mean square slope alone can be used to describe gas exchange for both cases. In addition Schmidt number scaling for tracers with medium solubility was investigated. Schmidt number scaling is a common method to compute the transfer resistance of a tracer using another one. This requires that the air-side or water-side transfer resistance are negligible. This is not the case for tracers with medium solubility. Here an extended Schmidt number scaling method is tested experimentally for the first time. The air-sided resistance is determined by the Schmidt number scaling with a very well soluble reference-tracer (Methanol, alpha = 5470). Accordingly the water-sided resistance is calculated with a water-sided controlled reference-tracer (N2O, alpha = 0.6). The total resistance is obtained using both parts of the resistance and the partitioning equation of Liss and Slater (1974). The comparison of computed and measured resistances shows good agreement. Finally, a simple function to empirically describe the ratio of air-sided to total resistance in dependence of friction velocity and solubility is presented.}, url = {http://www.ub.uni-heidelberg.de/archiv/13010}, author = {Christine Kr{\"a}uter} } @conference {kraeuter2011, title = {A comparative lab study of tansfer velocities of volatile tracers with widely varying solubilities}, booktitle = {DPG Fr{\"u}hjahrstagung Dresden, Fachverband Umweltphysik}, year = {2011}, abstract = {Die L{\"o}slichkeit einer fl{\"u}chtigen Substanz in Wasser hat einen entscheidenden Einfluss auf den Gasaustausch zwischen Ozean und Atmosph{\"a}re. Bei Stoffen mit einer sehr hohen L{\"o}slichkeit wird der Austausch durch Diffusion in der luftseitigen Grenzschicht kontrolliert und bei solchen mit einer sehr niedrigen L{\"o}slichkeit von der wasserseitigen Grenzschicht. Bei vielen umweltrelevanten Stoffen (z.B. Aceton, Acetaldehyd, Acetonitril) ist es aber ein Wechselspiel von beiden Prozessen. Die Kombination der Prozesse ist bisher experimentell nicht untersucht worden und es gibt nur einfache Modelle, welche die Intermittenz der Prozesse ber{\"u}cksichtigen. In einem ersten Laborexperiment am Aeolotron, einem ringf{\"o}rmigen Wind-Wellen-Kanal, wurden die Transferwiderst{\"a}nde vieler Gase mit unterschiedlichen L{\"o}slichkeiten bei verschiedenen Windgeschwindigkeiten (1,4 m/s bis 8,4 m/s) bestimmt. Die dimensionslosen L{\"o}slichkeiten der verwendeten Gase deckten einen Bereich von 5 Gr{\"o}{\ss}enordnungen ab. Die Gaskonzentrationen wurden durch FTIR-Spektroskopie (Fourier Transform Infrared Spectroscopy) und mit einem PTR-MS (Proton Transfer Reaction - Mass Spectrometer) gemessen. Die Partitionierung des Transferwiderstandes von Gasen mittlerer L{\"o}slichkeit in einen luftseitigen und wasserseitigen Teil konnte nachgewiesen werden.}, doi = {10.5281/zenodo.12327}, url = {http://www.dpg-verhandlungen.de/year/2011/conference/dresden/part/up/session/1/contribution/29}, author = {Christine Kr{\"a}uter and Kerstin E. Richter and Bernd J{\"a}hne and Evridiki Mesarchaki and Jonathan Williams} }