Central to modelling and estimating gas fluxes across the sea surface is the rate at which gases move from sea to air, and vice versa. The kinetics of the process are characterised by a transfer velocity (k), which is often parameterised in terms of wind speed. In ASGAMAGE, field measurements using purposefully added tracers were used to relate k to wind speed and other geophysical parameters.
Transfer velocity measurements were made during October/November 1996 in the southern North Sea from the RRS Challenger using double (SF6 /3He) and triple (SF6/ 3He/ bacterial spores) purposefully added tracers. These results were compared with estimates of k made using eddy correlation approaches from the adjacent fixed platform Meetpost Noordwijk. Simultaneous measurements of concentrations of trace gases such as DMS, CO2, CO, CH4, N2O, and NMHCs will be made so that, by combining them with the k values, air-sea fluxes can be obtained.
ASGAMAGE was part of the larger EC funded project of the same name. However, the RRS Challenger was the platform from which the dual and triple tracers were deployed and from which the climatically important trace gas concentration fields were measured.
