Investigation of small-scale air-sea interaction processes by active thermography

Active thermography is a non-contact instrumentation that can be used to investigate small-scale air-sea interaction processes at a footprint of a square meter and with time constants of minutes. It can be used also in large wind/wave facilities. Therefore it is a very useful instrument to investigate the mechanisms of air-sea gas transfer. The principles of the measurement technique are explained. Measurements from the Baltic Sea and the large annular Heidelberg Air-Sea Interaction Facility (Aeolotron) show the large variability of the gas exchange with the wave field and surface films.