Thermographic measurements of the temperature difference across the air- water interface: results from experimental and numerical studies

Thermography is a powerful tool for analyzing spatially and temporally resolved the transport of heat across the air-water interface. In this contribution, measurements of the temperature difference across the aqueous boundary layer will be presented. These measurements are based on a statistical analysis of the temperature distribution directly at the water surface. This technique will be presented together with results of measurements conducted in the laboratory and in the field. These thermographic measurements are compared to measurements with standard techniques. Also, the same statistical analysis is performed on data from direct numerical simulation of a wind-driven, aqueous turbulent boundary-layer flow. The agreement between thermography and simulation is very good. Moreover, the full 3D simulations are used for a thorough analysis and validation of the thermographic technique and help to discuss the results.