„Surface Ocean Processes in the Anthropocene“ (BMBF),
Subproject 4.3: Determination of the transfer velocity by a combined CO2/O2 surface water budget
Bernd Schneider, Robert Schmidt
Continuous measurements of the partial pressure of CO2 and O2 are used to calculate temporal changes of the total CO2 (CT) and of the O2 concentrations in the surface water. A budget for both CO2 and O2 will be established for time intervals of days to weeks resulting in two independent mass balance equations. These allow the determination of the mean transfer velocity, since at stable surface water stratification the major sink/source terms for CO2 and O2 are the air-sea flux and the biological production. These measurements are performed on the cargo ship FINNMAID and on the research platform FINO2. The mean transfer velocities will be used to validate parameterizations evolving from the high resolution flux determinations by eddy covariance and by thermography.
Furthermore, measurements of the surface tension (σ) will be used to characterize the surface film coverage at different seasons corresponding to the state of biological production. The data will be related to both the eddy covariance and the budget derived flux data in order to estimate a “film factor” that may be included in any parameterization of the transfer velocity.