Variations of Sulfur Dioxide Deposition Velocity Resulting from Terrain-forced Mesoscale Circulations

Variations of dry deposition velocity for S02 due to terrain-forced mesoscale circulations have been explored for northeast Colorado and south Florida. A mesoscale numerical model was used to obtain the wind and turbulence data needed to calculate the deposition velocities. Computations were performed both with and without consideration of observed land use characteristics. The results indicate that while variations in land use often dominate mesoscale variations of deposition velocity, mesoscale circulations can produce regions of enhanced deposition velocity. We recommend that simultaneous measurements of deposition velocity be made at multiple sites within a region in order to clarify the influence of terrain-forced mesoscale circulations on dry deposition. Key word index: Acid deposition, air pollution, dry deposition, numerical modeling, sea breezes, sulfur dioxide.