COI Funded Project: Validation of the Use of Heat as a Proxy Tracer for Gases in Air-Sea Exchange


Project Funded: 2002
Key Words: Gas Exchange, Heat Transfer, Infrared Imaging, Surface Renewal,  Carbon Dioxide 

Proposed Research

Air-sea exchange of biologically and climatologically important gases such as O 2 and CO 2 is driven largely by wind, which generates small-scale waves and enhances turbulent mixing at the ocean surface.   Field studies of the physical mechanisms governing gas exchange are limited by current methods for measuring gas fluxes and transfer rates, which require averaging over scales of time and space that are large relative to scales of variability in the atmosphere and the ocean surface.   This is particularly important in the highly variable coastal regime, where rapid shifts in local winds, atmospheric stability, currents, tidal mixing, and surface film distributions impact gas exchange on short time scales.


Heat transfer rates can be estimated from infrared imagery of the sea surface on very short time scales using advanced digital image processing techniques.   It has been suggested that these could be extrapolated to yield gas transfer rates using an appropriate surface renewal model.   An experiment is proposed to evaluate the use of heat as a proxy tracer for gases in exchange processes by directly comparing gas and heat fluxes in a large wind-wave flume.   A successful validation would provide a powerful tool for field studies of air-sea gas exchange in the coastal regime and underpin future research in this area.