Heidelberg 2006 – scientific programme
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UP: Umweltphysik
UP 1: Hydrosph
äre
UP 1.2: Fachvortrag
Monday, March 13, 2006, 14:30–14:45, A
Active Thermography: a local and fast method to investigate heat and gas exchange between ocean and atmosphere — •Uwe Schimpf1, Christopher Popp1, and Bernd Jähne1,2 — 1Institute for Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 678, 69120 Heidelberg — 2Interdisciplinary Center for Scientific Computing, University of Heidelberg, Im Neuenheimer Feld 368, 69120 Heidelberg
The exchange of heat, mass and momentum between atmosphere and ocean is dominated by the interaction of turbulent transport and molecular diffusion in the boundary layer that is still only poorly understood. A new variant of active thermography gives a direct insight into the transport mechanisms. A carbon dioxide laser forces a periodically varying heat flux density onto the water surface and the amplitude damping and phase shift of the sea surface temperature is measured from infrared image sequences. In this way, the transport process can be treated by linear system theory and the relation between the input signal (periodically varying surface flux density) and the output (surface temperature) is estimated. From these measurements the transfer velocity can be determined. In addition, a direct comparison with different theoretical models of air-sea gas exchange is possible. A first analysis of laboratory experiments from the Heidelberg Aeolotron (wind-wave facility) indicates that the exchange process is strongly intermittent.