Micrometeorology of air/sea fluxes of carbon dioxide and dimethylsulphide
Micrometeorologie van lucht/zee fluxen van CO2 en dimethylsulfide
Stoll MHC , Baar de HJW , Zemmelink HJ , Klaassen W , Gieskes WWC
RIVM Report 410200085
The sea to air flux of CO2 and the biogenic volatile sulfur compound dimethylsulphide were assessed with the Relaxed Eddy Accumulation (REA) and the Gradient Flux techniques from stationary and moving platforms in the Atlantic and Pacific Oceans during the FAIRS and GasEx cruise. The correlation between the techniques was good, with REA on average higher than GF. Fluxes derived from micrometeorological measurements agreed within error bars with those obtained by the conventional equations as proposed by Liss and Merlivat (1986), Wanninkhof (1992), and Jacobs (1999). The relationships between the transfer velocity and wind speed based on the micrometeorological measurements agreed within 10% and were on average higher than the equation proposed by Wanninkhof (1992). The effect of temperature on the computed sea to air flux of CO2 were investigated on a micrometeorological scale as well as on a small scale (top few metres of the watercolumn). The definition of skin temperature relies on a known bulk temperature of the water, which is shown to be not only highly stratified in the thermal structure but also very resilient versus disturbances, being wind speed. The skin temperature models, which were derived from open ocean work, are not directly applicable to coastal seas. As the skin temperature and the thermal structure is so rigid under the various wind conditions the gas exchange coefficients, derived from windtunnel experiments under the assumption of a well mixed layer are now under scrutiny.