Alex Vermeulen
Chef
Evaluation of SO2 dry deposition over short vegetation in Portugal
Författare
Summary, in English
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 R-c 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 R-c increases by a factor of two, but SO2 deposition rates then still are significant. The parameterisation of the surface resistance for SO2 proved to be difficult, but V-d 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. (C) 2001 Published by Elsevier Science Ltd.
Publiceringsår
2001
Språk
Engelska
Sidor
3633-3643
Publikation/Tidskrift/Serie
Atmospheric Environment
Volym
35
Issue
21
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Meteorology and Atmospheric Sciences
Nyckelord
- sulfur dioxide
- dry deposition
- vegetation
- Portugal
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1352-2310