Quantitative Imaging of Small-Scale Air-Water Interaction Processes in Lab and Field
Event details
| Date | 13.05.2014 |
| Hour | 16:15 › 17:15 |
| Speaker | Dr Bernd Jaehne, Heidelberg Collaboratory for Image Processing (HCI) IWR, Universität Heidelberg, Germany |
| Location | |
| Category | Conferences - Seminars |
Abstract:
“On the open sea, the microlayer is almost inaccessible to direct physical measurements” [Hasse, 1997]. Indeed, classical mass balance techniques, which estimate mean transfer velocities over large spatial and temporal scales, are only suitable for a parametrization of the transfer process with the parameters controlling it. Direct insight into the mechanisms of air-water gas transfer, however, is given by techniques that provide a spatio-temporal quantitative imaging of all the parameters that determine the mass exchange process within the microlayer at the water surface. This includes the turbulent shear flow, concentration fields of dissolved gases, and the shape of the ocean surfaces undulated by wind-driven waves. At higher wind speeds, when waves are breaking, it is also required to visualise bubbles and droplets.
While numerical approaches and also all kinds of flow visualization techniques in general have made significant progress in the last years, progress in quantitative imaging to investigate small-scale air-sea interaction processes is still slow, because imaging techniques are experimentally very demanding even in laboratory facilities. This is because the interface is moving, being deformed by waves and sometimes breaks. Thus the lack of adequate quantitative imaging techniques is one of the major obstacles in gaining a better understanding of the mechanisms of air-sea gas transfer. Most previous investigations were limited to the simpler case of flat free water surfaces and used only various kinds of bottom-generated turbulence. This talk gives a survey on imaging techniques for short wind-waves, passive and active thermography to study surface flow, heat and mass transfer at the water surface, and fluorescence techniques for high-resolution imaging of concentration fields in the vicinity of the air-water interface.
Short biography:
Bernd Jähne is Physicist and Computer Scientist, educated at the Universities of Saarbrücken, Heidelberg and Hamburg-Harburg. After a research professorship at the Scripps Institution of Oceanography (UCSD), he occupies a professorship in image processing at the Interdisciplinary Center for Scientific Computing (IWR) and the Institute of Environmental Physics of Heidelberg University since 1994. Since 2008 he is also coordinating director of the industry on campus project Heidelberg Collaboratory for Image Processing (HCI).
“On the open sea, the microlayer is almost inaccessible to direct physical measurements” [Hasse, 1997]. Indeed, classical mass balance techniques, which estimate mean transfer velocities over large spatial and temporal scales, are only suitable for a parametrization of the transfer process with the parameters controlling it. Direct insight into the mechanisms of air-water gas transfer, however, is given by techniques that provide a spatio-temporal quantitative imaging of all the parameters that determine the mass exchange process within the microlayer at the water surface. This includes the turbulent shear flow, concentration fields of dissolved gases, and the shape of the ocean surfaces undulated by wind-driven waves. At higher wind speeds, when waves are breaking, it is also required to visualise bubbles and droplets.
While numerical approaches and also all kinds of flow visualization techniques in general have made significant progress in the last years, progress in quantitative imaging to investigate small-scale air-sea interaction processes is still slow, because imaging techniques are experimentally very demanding even in laboratory facilities. This is because the interface is moving, being deformed by waves and sometimes breaks. Thus the lack of adequate quantitative imaging techniques is one of the major obstacles in gaining a better understanding of the mechanisms of air-sea gas transfer. Most previous investigations were limited to the simpler case of flat free water surfaces and used only various kinds of bottom-generated turbulence. This talk gives a survey on imaging techniques for short wind-waves, passive and active thermography to study surface flow, heat and mass transfer at the water surface, and fluorescence techniques for high-resolution imaging of concentration fields in the vicinity of the air-water interface.
Short biography:
Bernd Jähne is Physicist and Computer Scientist, educated at the Universities of Saarbrücken, Heidelberg and Hamburg-Harburg. After a research professorship at the Scripps Institution of Oceanography (UCSD), he occupies a professorship in image processing at the Interdisciplinary Center for Scientific Computing (IWR) and the Institute of Environmental Physics of Heidelberg University since 1994. Since 2008 he is also coordinating director of the industry on campus project Heidelberg Collaboratory for Image Processing (HCI).
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. D. Andrew Barry, ECOL