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Advisor(s)
Abstract(s)
SO2 dry deposition was studied over short vegetation, in Portugal, by means of the concentration gradient method.
The experimental study involved one first phase of long-term measurements carried out in a grassland and, subsequently,
a second period of several 1997 intensive field campaigns performed in three places representing different climate and
surface conditions. Temporal and spatial patterns of dry deposition parameters show that downward fluxes of SO2 are
by some extent affected by surface processes. Median Rc varied from 140 s cm-1 to values around 200 s cm-1, in a wide
range of environmental conditions. Stomatal uptake is an important sink when vegetation is biologically active, but its
contribution is effectively low when compared with non-stomatal mechanisms, especially when the surface is wet. Under
dry conditions Rc increases by a factor of two, but SO2 deposition rates then still are signifficant. The parameterisation of
the surface resistance for SO2 proved to be difficult, but Vd derived with the Erisman parameterisation (Erisman et al.,
Atmos. Environ. 28 (16) (1994) 2595) compared best with measured values, at low time resolution scale and especially
under moisture conditions.
Description
Keywords
Sulfur dioxide Dry deposition Vegetation Portugal
Citation
Feliciano, Manuel; Pio, Casimiro; Vermeulen, Alex (2001). Evaluation of SO2 dry deposition over short vegetation in Portugal. Atmospheric Environment. ISSN 1352-2310. 35:21, p. 3633-3643