Isoprene emission fluxes determined by an atmospheric tracer techniquE

Sulfur hexafluoride tracer was used in a series of experiments to simulate isoprene emissions from an isolated oak grove. The measured tracer release rate and ambient concentrations of isoprene and SF6 observed along downwind sample lines were combined to determine the mass flux of isoprene from the forest. The fluxes determined from the tracer data increased exponentially with temperature and were in close agreement with estimates determined from emission rates measured in a series of branch enclosure samples. The results of this field study demonstrate the feasibility and usefulness of simulating forest emissions as a tool for investigating turbulent transport in forested areas. Isoprene emission fluxes that can be applied in regional models are reported.