MEASUREMENTS OF AEROSOL FLUXES TO SPEULDER FOREST USING A MICROMETEOROLOGICAL TECHNIQUE

It has often been stated that micrometeorological and throughfall meas urements of dry deposition differ by an order of magnitude with the re sults being highly variable and difficult to interpret or reconcile. W e present measurements by the eddy correlation method of sub-micron ae rosol deposition to a forest and show that they are large, typically 1 cm s(-1) or more. We compare the measurements with literature values obtained by throughfall and related techniques. The results, rather th an being irreconcilable, show a clear and consistent behaviour in depo sition velocity across the aerosol size spectrum, despite the very dif ferent techniques involved. There would appear to be a contradiction w ith previously assumed model predictions of aerosol deposition Velocit y to forests and rough vegetated surfaces particularly for particles i n the size range 0.1-1.0 mu m where collection efficiencies appear to be significantly underestimated A simple deposition velocity parameter isation as a function of stability and size is presented. Copyright (C ) 1996 Elsevier Science Ltd