Ozone fluxes above and within a pine forest canopy in dry and wet conditions

Lamaud, Éric; Carrara, Arnaud; Brunet, Yves; Lopez, A.; Druilhet, A.

doi:10.1016/s1352-2310(01)00468-x

Cited by 92 publications

(66 citation statements)

References 39 publications

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“…However, it is comparable to findings above temperate forests during summer (daytime means of about 0.4 cm s −1 by Lamaud et al, 2002; and about 0.6 cm s −1 by Munger et al, 1996) and recent results of Matsuda et al (2005) from a partly leafless tropical savanna teak forest during the dry season in northern Thailand (ca. 0.4 cm s −1 ).…”

Section: Mean Deposition Velocities and Fluxessupporting

confidence: 89%

“…Since previous dry season O 3 studies in the tropics (see Table 1) did not consider the O 3 storage change term and only a small influence from it was reported for temperate forests (e.g. Lamaud et al, 2002;Munger et al, 1996), our dry season results represent the highest ozone storage effects in forest deposition experiments reported so far. Table 1 gives a survey of mean fluxes and deposition velocities determined in this study together with results for tropical rain forest reported in the literature.…”

Section: Difference Between Measured Flux and Actual Depositionmentioning

confidence: 90%

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Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

et al. 2007

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Abstract. Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution toLarge-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH), we performed tower-based eddy covariance measurements of O 3 flux above an Amazonian primary rain forest at the end of the wet and dry season. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O 3 sink with a mean daytime (midday) maximum deposition velocity of 2.3 cm s −1 , and a corresponding O 3 flux of −11 nmol m −2 s −1 . At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb) than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O 3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s −1 . The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO) was found to contribute substantially to the O 3 sink in the rain forest canopy. Further contributions Correspondence to: U. Rummel (udo.rummel@dwd.de) were from non-stomatal plant uptake and other processes that could not be clearly identified.Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O 3 dry deposition values from this site with typical vegetation cover of deforested land in southwest Amazonia to the results from the primary rain forest. The mean ozone deposition to the pasture was found to be systematically lower than that to the forest by 30% in the wet and 18% in the dry season.

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Section: Mean Deposition Velocities and Fluxessupporting

confidence: 89%

Section: Difference Between Measured Flux and Actual Depositionmentioning

confidence: 90%

Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

et al. 2007

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“…Similar results/reports on long-term measurement of ozone fluxes at the ecosystem level are rather limited (Zhang et al, 2002;Turnispeed et al, 2009;Fares et al, 2010). Nevertheless, extensive ozone deposition studies over different ecosystems have been performed in order to understand deposition mechanisms and possible harmful effect on ecosystems (e.g., Fowler et al, 2001;Lamaud et al, 2002;Goldstein et al, 2004;Holzinger et al, 2005Holzinger et al, , 2006Altimir et al, 2006;Mészáros et al, 2009;Lamaud et al, 2009;Coyle et al, 2009).…”

Section: Introductionmentioning

confidence: 87%

Ozone deposition into a boreal forest over a decade of observations: evaluating deposition partitioning and driving variables

et al. 2012

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Abstract. This study scrutinizes a decade-long series of ozone deposition measurements in a boreal forest in search for the signature and relevance of the different deposition processes. The canopy-level ozone flux measurements were analysed for deposition characteristics and partitioning into stomatal and non-stomatal fractions, with the main focus on growing season day-time data. Ten years of measurements enabled the analysis of ozone deposition variation at different time-scales, including daily to inter-annual variation as well as the dependence on environmental variables and concentration of biogenic volatile organic compounds (BVOCs). Stomatal deposition was estimated by using multi-layer canopy dispersion and optimal stomatal control modelling from simultaneous carbon dioxide and water vapour flux measurements, non-stomatal was inferred as residual. Also, utilising the big-leaf assumption stomatal conductance was inferred from water vapour fluxes for dry canopy conditions. The total ozone deposition was highest during the peak growing season (4 mm s −1 ) and lowest during winter dormancy (1 mm s −1 ). During the course of the growing season the fraction of the non-stomatal deposition of ozone was determined to vary from 26 to 44 % during day time, increasing from the start of the season until the end of the growing season. By using multi-variate analysis it was determined that day-time total ozone deposition was mainly driven by photosynthetic capacity of the canopy, vapour pressure deficit (VPD), photosynthetically active radiation and monoterpene concentration. The multi-variate linear model explained the high portion of ozone deposition variance on daily average level (R 2 = 0.79). The explanatory power of the multivariate model for ozone non-stomatal deposition was much lower (R 2 = 0.38). The set of common environmental variables and terpene concentrations used in multivariate analysis were able to predict the observed average seasonal variation in total and non-stomatal deposition but failed to explain the inter-annual differences, suggesting that some still unknown mechanisms might be involved in determining the inter-annual variability. Model calculation was performed to evaluate the potential sink strength of the chemical reactions of ozone with sesquiterpenes in the canopy air space, which revealed that sesquiterpenes in typical amounts at the site were unlikely to cause significant ozone loss in canopy air space. The results clearly showed the importance of several non-stomatal removal mechanisms. Unknown chemical compounds or processes correlating with monoterpene concentrations, including potentially reactions at the surfaces, contribute to non-stomatal sink term.

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“…Although this may not be particularly important for O 3 , dry deposition of the gas at the earth's surface is affected by surface wetness (Altimir et al, 2006;Grantz et al, 1995;Lamaud et al, 2002), and by the state of vegetation, in particular its uptake through stomata. Increased CO 2 concentrations may inhibit O 3 uptake directly, by reducing stomatal conductance (Harmens et al, 2007;Sanderson et al, 2007;Tausz et al, 2007).…”

Section: Dry and Wet Depositionmentioning

confidence: 99%

Surface ozone concentrations and ecosystem health: Past trends and a guide to future projections

Cape

2008

Science of The Total Environment

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This paper reviews current understanding of the sources and sinks of ozone in the troposphere, recent studies of long-term trends, and the factors which have to be taken into consideration when constructing and interpreting future models of ozone concentration. The factors controlling surface O 3 concentrations are discussed initially to provide a basis for the ensuing discussion, followed by a summary of the evidence for recent trends in ground-level ozone concentrations, i.e. over the past 3 decades, which have shown a significant increase in the annual average in 'background' air typical of the unpolluted northern hemisphere. Closer to precursor sources, although urban winter concentrations have increased, rural peak spring and summer concentrations during ozone 'episodes' have decreased markedly in response to emissions reductions. In order to determine whether such trends are meaningful, the statistical techniques for determining temporal trends are reviewed. The possible causes of long-term trends in ozone are then discussed, with particular reference to the use of chemistry-transport models to interpret past trends. Such models are also used to make predictions of future trends in surface ozone concentrations, but few are comprehensive in integrating future climate changes with changes in land use and in emissions of ozone precursors. Guidance is given on the likely effects of climate/precursor/chemistry interactions so that model predictions can be judged.

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Ozone fluxes above and within a pine forest canopy in dry and wet conditions

Cited by 92 publications

References 39 publications

Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

Ozone deposition into a boreal forest over a decade of observations: evaluating deposition partitioning and driving variables

Surface ozone concentrations and ecosystem health: Past trends and a guide to future projections

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