Characteristics of an Ozone Deposition Module

Simpson, David; Tuovinen, J.-R; Emberson, Lisa; Ashmore, Mike

doi:10.1007/978-94-010-9026-1_25

Cited by 30 publications

(47 citation statements)

References 9 publications

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“…Details of the dry deposition module are given in Simpson et al (2003a). For ozone the methods have been extensively described in a series of articles (Emberson et al, 2000Simpson et al, 2001Simpson et al, , 2003bTuovinen et al, 2001Tuovinen et al, , 2004. A thorough description of the model is included in Simpson et al (2003a), with updates reported in Fagerli et al (2004).…”

Section: Description Of the Emep Modelmentioning

confidence: 99%

Can we explain the trends in European ozone levels?

et al. 2006

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Abstract. Ozone levels in Europe are changing. Emissions of ozone precursors from Europe (NO x , CO and nonmethane hydrocarbons) have been substantially reduced over the last 10-15 years, but changes in ozone levels cannot be explained by changes in European emissions alone. The observed ozone trends at many European sites are only partially reproduced by global or regional photochemistry models, and possible reasons for this are discussed.In order to further explain the European trends in ozone since 1990, the EMEP regional photochemistry model has been run for the years 1990 and 1995-2002. The EMEP model is a regional model centred over Europe but the model domain also includes most of the North Atlantic and the polar region. Climatological ozone data are used as initial and lateral boundary concentrations. Model results are compared to measurements over this timespan of 12 years. Possible causes for the measured trends in European surface ozone have been investigated using model sensitivity runs perturbing emissions and lateral boundary concentrations. The increase in winter ozone partially, and the decrease in the magnitude of high ozone episodes, is attributed to the decrease in ozone precursor emissions since 1990 by the model. Furthermore, the model calculations indicate that the emission reductions have resulted in a marked decrease in summer ozone in major parts of Europe, in particular in Germany. Such a trend in summer ozone is likely to be difficult to identify from the measurements alone because of large inter-annual variability.

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Section: Description Of the Emep Modelmentioning

confidence: 99%

Can we explain the trends in European ozone levels?

et al. 2006

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“…The stomatal conductance algorithm was originally developed for the calculation of ozone fluxes, and has been extensively documented (Emberson et al, 2000a,b,c;Simpson et al, , 2003bTuovinen et al, 2001Tuovinen et al, , 2004. The non-stomatal deposition of O 3 is treated with a resistance formulation for the external leaf-surface and the ground surface, along with an in-canopy resistance between the leaf-level and ground-surface.…”

Section: The Eulerian Emep Modelmentioning

confidence: 99%

Comparison of modelled and monitored deposition fluxes of sulphur and nitrogen to ICP-forest sites in Europe

et al. 2006

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Abstract. The EMEP MSC-W Eulerian chemical transport model, and its predictions of deposition of acidifying and eutrophying pollutants over Europe, play a key role in the development of emission control strategies for Europe. It is important that this model is tested against observational data. Concerning precipitation, the EMEP model and ICP network showed very similar overall levels (within 4% for 1997 and 11% for 2000). The correlation was, however, poor (r 2 =0.15-0.23). This can be attributed largely to the influence of a few outliers, combined with a small range of rainfall amounts for most points. Correlations between modelled and observed deposition values in this study were rather high (r 2 values between 0.4-0.8 for most components and years), with mean values across all sites being within 30%. The EMEP model tends to give somewhat lower values for SO in precipitation are very similar on average (differences of 0-14%), with good correlation between modelled and observed data (r 2 =0.50-0.78). Differences between the EMEP model and ICP measurements are thought to arise from a mixture of problems with both the observations and model. However, the overall conclusion is that the EMEP model performs rather well in reproducing patterns of S and N deposition to European forests.

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“…The biological action in the process of ozone deposition is introduced most commonly through a description of stomatal behaviour based on measurements or estimations of transpiration (Baldocchi et al, 1987;Meyers et al, 1998;Simpson et al, 2003), which predict the dynamics of stomatal aperture to govern the deposition during the active seasons and explain most of the daily and annual pattern. However, taking into account turbulent and diffusive transport , the stomatal uptake is not sufficient to predict the magnitude of the canopy sink.…”

Section: Introductionmentioning

confidence: 99%

Foliage surface ozone deposition: a role for surface moisture?

et al. 2006

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Abstract. This paper addresses the potential role of surface wetness in ozone deposition to plant foliage. We studied Scots pine foliage in field conditions at the SMEARII field measurement station in Finland. We used a combination of data from flux measurement at the shoot (enclosure) and canopy scale (eddy covariance), information from foliage surface wetness sensors, and a broad array of ancillary measurements such as radiation, precipitation, temperature, and relative humidity. Environmental conditions were defined as moist during rain or high relative humidity and during the subsequent twelve hours from such events, circumstances that were frequent at this boreal site. From the measured fluxes we estimated the ozone conductance using it as the expression of the strength of ozone removal surface sink or total deposition. Further, we estimated the stomatal contribution and the remaining deposition was interpreted and analysed as the non-stomatal sink.The combined time series of measurements showed that both shoot and canopy-scale ozone total deposition were enhanced when moist conditions occurred. On average, the estimated stomatal deposition accounted for half of the measured removal at the shoot scale and one third at the canopy scale. However, during dry conditions the estimated stomatal uptake predicted the behaviour of the measured deposition, but during moist conditions there was disagreement. The estimated non-stomatal sink was analysed against several environmental factors and the clearest connection was found with ambient relative humidity. The relationship disappeared under 70% relative humidity, a threshold that coincides with the value at which surface moisture gathers at the foliage surface according to the leaf surface wetness measurements. This suggests the non-stomatal ozone sink on the foliage to be modulated by the surface films. We attempted to extract such potential modulation with the estimated film formation viaCorrespondence to: N. Altimir (nuria.altimir@helsinki.fi) the theoretical expression of adsorption. Whereas this procedure could predict the behaviour of the non-stomatal sink, it implied a chemical sink that was not accountable as simple ozone decomposition. We discuss the existence of other mechanisms whose relevance in the removal of ozone needs to be clarified, in particular: a significant nocturnal stomatal aperture neglected in the estimations, and a potentially large chemical sink offered by reactive biogenic organic volatile compounds.

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Characteristics of an Ozone Deposition Module

Cited by 30 publications

References 9 publications

Can we explain the trends in European ozone levels?

Can we explain the trends in European ozone levels?

Comparison of modelled and monitored deposition fluxes of sulphur and nitrogen to ICP-forest sites in Europe

Foliage surface ozone deposition: a role for surface moisture?

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