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| Titel |
DO3SE modelling of soil moisture to determine ozone flux to forest trees |
| VerfasserIn |
P. Büker, T. Morrissey, A. Briolat, R. Falk, D. Simpson, J.-P. Tuovinen, R. Alonso, S. Barth, M. Baumgarten, N. Grulke, P. E. Karlsson, J. King, F. Lagergren, R. Matyssek, A. Nunn, R. Ogaya, J. Peñuelas, L. Rhea, M. Schaub, J. Uddling, W. Werner, L. D. Emberson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 12 ; Nr. 12, no. 12 (2012-06-25), S.5537-5562 |
| Datensatznummer |
250011284
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| Publikation (Nr.) |
 copernicus.org/acp-12-5537-2012.pdf |
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| Zusammenfassung |
The DO3SE (Deposition of O3 for Stomatal Exchange) model is an
established tool for estimating ozone (O3) deposition, stomatal flux
and impacts to a variety of vegetation types across Europe. It has been
embedded within the EMEP (European Monitoring and Evaluation Programme)
photochemical model to provide a policy tool capable of relating the
flux-based risk of vegetation damage to O3 precursor emission scenarios
for use in policy formulation. A key limitation of regional flux-based risk
assessments has been the assumption that soil water deficits are not
limiting O3 flux due to the unavailability of evaluated methods for
modelling soil water deficits and their influence on stomatal conductance
(gsto), and subsequent O3 flux.
This paper describes the development and evaluation of a method to estimate
soil moisture status and its influence on gsto for a variety of
forest tree species. This DO3SE soil moisture module uses the
Penman-Monteith energy balance method to drive water cycling through the
soil-plant-atmosphere system and empirical data describing gsto relationships with pre-dawn leaf water status to estimate the biological
control of transpiration. We trial four different methods to estimate this
biological control of the transpiration stream, which vary from simple
methods that relate soil water content or potential directly to gsto,
to more complex methods that incorporate hydraulic resistance and plant
capacitance that control water flow through the plant system.
These methods are evaluated against field data describing a variety of soil
water variables, gsto and transpiration data for Norway spruce
(Picea abies), Scots pine (Pinus sylvestris), birch (Betula pendula),
aspen (Populus tremuloides), beech (Fagus sylvatica) and holm oak
(Quercus ilex) collected
from ten sites across Europe and North America. Modelled estimates of these
variables show consistency with observed data when applying the simple
empirical methods, with the timing and magnitude of soil drying events being
captured well across all sites and reductions in transpiration with the
onset of drought being predicted with reasonable accuracy. The more complex
methods, which incorporate hydraulic resistance and plant capacitance,
perform less well, with predicted drying cycles consistently underestimating
the rate and magnitude of water loss from the soil.
A sensitivity analysis showed that model performance was strongly dependent
upon the local parameterisation of key model drivers such as the maximum
gsto, soil texture, root depth and leaf area index. The
results suggest that the simple modelling methods that relate
gsto directly to soil water content and potential provide
adequate estimates of soil moisture and influence on gsto such
that they are suitable to be used to assess the potential risk posed by
O3 to forest trees across Europe. |
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