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Authors
Advisor(s)
Abstract(s)
Long-term measurements of SO2 and O3 dry
deposition were carried out during one year over a grass field, located in the west coast of Portugal. An automatic system based on micrometeorological techniques provided,
on a routine basis, an important data set for both gases. The results show strong daily and seasonal cycles in dry
deposition velocity and surface resistance, for ozone, being also verified a seasonal trend for SO2. For both gases maximum Rc values were observed in summertime with the
minimum values occurring in winter and spring. These differences match with surface conditions. In Portugal the vegetation reaches its maximum of activity in spring and
becomes partially dry in the end of summer, after several months without rainfall. The stomatal intake seems to be the most important controlling factor on dry deposition, specially for ozone. A parameterization of surface resistance for ozone based on conclusions from recent dry
deposition studies yields Re values in good agreement with the observed values. For SO2, Rc values are influenced by other factors besides stoma opening such as surface
wetness, being, therefore, more difficult to evaluate the applicability of existent parameterization schemes.
Description
Keywords
Gaseous pollutants Dry deposition Eddy correlation Gradient method Portugal
Citation
Pio, Casimiro; Feliciano, Manuel (1996). Dry deposition of ozone and sulphur dioxide over low vegetation in moderate southern European weather conditions. Measurements and modeling. Physics and Chemistry of the Earth. ISSN 0079-1946. 21: 5-6, p. 373-377
Publisher
Elsevier