title: Comparison of seasonal variations of ozone exposure and fluxes in a Mediterranean Holm oak forest between the exceptionally dry 2003 and the following year.
abstract: Ozone and energy fluxes have been measured using the eddy covariance technique, from June to December 2004 in Castelporziano near Rome (Italy), and compared to similar measurements made in the previous year. The studied ecosystem consisted in a typical Mediterranean Holm oak forest. Stomatal fluxes have been calculated using the resistance analogy and by inverting the Penmann-Monteith equation. Results showed that the average stomatal contribution accounts for 42.6% of the total fluxes. Non-stomatal deposition proved to be enhanced by increasing leaf wetness and air humidity during the autumnal months. From a comparison of the two years, it can be inferred that water supply is the most important limiting factor for ozone uptake and that prolonged droughts alter significantly the stomatal conductance, even 2 months after the soil water content is replenished. Ozone exposure, expressed as AOT40, behaves similarly to the cumulated stomatal flux in dry conditions whereas a different behaviour for the two indices appears in wet autumnal conditions. A difference also occurs between the two years.
authors.affiliation: Department of Mathematics and Physics, Catholic University of the Sacred Heart, Via Musei 41, 25121 Brescia, BS, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Gerosa
authors.forename: Angelo
authors.initials: A
authors.lastname: Finco
authors.forename: Simone
authors.initials: S
authors.lastname: Mereu
authors.forename: Marcello
authors.initials: M
authors.lastname: Vitale
authors.forename: Fausto
authors.initials: F
authors.lastname: Manes
authors.forename: Antonio Ballarin
authors.initials: AB
authors.lastname: Denti
mesh_terms: D000393:Air Pollutants / Q000032:analysis* / Q000378:metabolism; D055864:Droughts; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods; D006358:Hot Temperature; D006813:Humidity; D007558:Italy; D010083:Oxidants, Photochemical / Q000032:analysis* / Q000378:metabolism; D054046:Plant Stomata / Q000378:metabolism; D029963:Quercus / Q000187:drug effects / Q000378:metabolism*; D012621:Seasons; D013464:Sulfuric Acids / Q000032:analysis* / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D010083:Oxidants, Photochemical; D013464:Sulfuric Acids; C048813:potassium peroxymonosulfuric acid