The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range ...Transboundary Air Pollution (CLRTAP) for more than 30 years. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments. Traditionally, the model has covered all of Europe with a resolution of about 50 km × 50 km, and extending vertically from ground level to the tropopause (100 hPa). The model has changed extensively over the last ten years, however, with flexible processing of chemical schemes, meteorological inputs, and with nesting capability: the code is now applied on scales ranging from local (ca. 5 km grid size) to global (with 1 degree resolution). The model is used to simulate photo-oxidants and both inorganic and organic aerosols. In 2008 the EMEP model was released for the first time as public domain code, along with all required input data for model runs for one year. The second release of the EMEP MSC-W model became available in mid 2011, and a new release is targeted for summer 2012. This publication is intended to document this third release of the EMEP MSC-W model. The model formulations are given, along with details of input data-sets which are used, and a brief background on some of the choices made in the formulation is presented. The model code itself is available at www.emep.int, along with the data required to run for a full year over Europe.
We analysed the effect of the 2018 European drought on greenhouse gas (GHG) exchange of five North European mire ecosystems. The low precipitation and high summer temperatures in Fennoscandia led to ...a lowered water table in the majority of these mires. This lowered both carbon dioxide (CO
) uptake and methane (CH
) emission during 2018, turning three out of the five mires from CO
sinks to sources. The calculated radiative forcing showed that the drought-induced changes in GHG fluxes first resulted in a cooling effect lasting 15-50 years, due to the lowered CH
emission, which was followed by warming due to the lower CO
uptake. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.
Two very different types of approaches are currently in use today for indicating risk of ozone damage to vegetation in Europe. One approach is the so-called AOTX (accumulated exposure over threshold ...of
X
ppb) index, which is based upon ozone concentrations only. The second type of approach entails an estimate of the amount of ozone entering via the stomates of vegetation, the AFstY approach (accumulated stomatal flux over threshold of
Y
nmol
m
−2
s
−1). The EMEP chemical transport model is used to map these different indicators of ozone damage across Europe, for two illustrative vegetation types, wheat and beech forests. The results show that exceedences of critical levels for either type of indicator are widespread, but that the indicators give very different spatial patterns across Europe. Model simulations for year 2020 scenarios suggest reductions in risks of vegetation damage whichever indicator is used, but suggest that AOT40 is much more sensitive to emission control than AFstY values.
Model calculations of AOT40 and AFstY show very different spatial variations in the risks of ozone damage to vegetation.
Forests in Europe face significant changes in climate, which in interaction with air quality changes, may significantly affect forest productivity, stand composition and carbon sequestration in both ...vegetation and soils. Identified knowledge gaps and research needs include: (i) interaction between changes in air quality (trace gas concentrations), climate and other site factors on forest ecosystem response, (ii) significance of biotic processes in system response, (iii) tools for mechanistic and diagnostic understanding and upscaling, and (iv) the need for unifying modelling and empirical research for synthesis. This position paper highlights the above focuses, including the global dimension of air pollution as part of climate change and the need for knowledge transfer to enable reliable risk assessment. A new type of research site in forest ecosystems (“supersites”) will be conducive to addressing these gaps by enabling integration of experimentation and modelling within the soil-plant-atmosphere interface, as well as further model development.
► Research needs are identified for forests under climate change and air pollution. ► Abiotic–biotic interactions in response impede tree-ecosystem upscaling. ► Integration of empirical and modelling research is advocated. ► The concept of multi-scale investigations at novel “Supersites” is propagated. ► “Supersites” warrant mechanistic understanding of soil-plant-atmosphere interface.
Forests under climate change and air pollution require empirical and modelling research needs to be integrated at novel “Supersites” through multi-scale investigations.
Drainage for forestry purposes increases the depth of the oxic peat layer and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon ...dioxide (CO2), methane (CH4) and nitrous oxide (N2O) change: due to the accelerated decomposition of peat in the presence of oxygen, drained peatlands are generally considered to lose peat carbon (C). We measured CO2 exchange with the eddy covariance (EC) method above a drained nutrient-poor peatland forest in southern Finland for 16 months in 2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2–5-week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was −870 ± 100 g CO2 m−2 yr−1 in the calendar year 2005, indicating net CO2 uptake from the atmosphere. The site was a small sink of CH4 (−0.12 g CH4 m−2 yr−1) and a small source of N2O (0.10 g N2O m−2 yr−1). Photosynthesis was detected throughout the year when the air temperature exceeded −3 °C. As the annual accumulation of C in the above and below ground tree biomass (175 ± 35 g C m−2) was significantly lower than the accumulation observed by the flux measurement (240 ± 30 g C m−2), about 65 g C m−2 yr−1 was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown by EC measurements to occur in a forestry-drained peatland. Our results suggest that forestry-drainage may significantly increase the CO2 uptake rate of nutrient-poor peatland ecosystems.
Purpose Large mandibular resection defects historically have been treated using autogenous bone grafts and reconstruction plates. However, a major drawback of large autogenous bone grafts is ...donor-site morbidity. Patients and Methods This report describes the replacement of a 10-cm anterior mandibular ameloblastoma resection defect, reproducing the original anatomy of the chin, using a tissue-engineered construct consisting of β-tricalcium phosphate (β-TCP) granules, recombinant human bone morphogenetic protein-2 (BMP-2), and Good Manufacturing Practice–level autologous adipose stem cells (ASCs). Unlike prior reports, 1-step in situ bone formation was used without the need for an ectopic bone-formation step. The reconstructed defect was rehabilitated with a dental implant-supported overdenture. An additive manufactured medical skull model was used preoperatively to guide the prebending of patient-specific hardware, including a reconstruction plate and titanium mesh. A subcutaneous adipose tissue sample was harvested from the anterior abdominal wall of the patient before resection and simultaneous reconstruction of the parasymphysis. ASCs were isolated and expanded ex vivo over the next 3 weeks. The cell surface marker expression profile of ASCs was similar to previously reported results and ASCs were analyzed for osteogenic differentiation potential in vitro. The expanded cells were seeded onto a scaffold consisting of β-TCP and BMP-2 and the cell viability was evaluated. The construct was implanted into the parasymphyseal defect. Results Ten months after reconstruction, dental implants were inserted into the grafted site, allowing harvesting of bone cores. Histologic examination and in vitro analysis of cell viability and cell surface markers were performed and prosthodontic rehabilitation was completed. Conclusion ASCs in combination with β-TCP and BMP-2 offer a promising construct for the treatment of large, challenging mandibular defects without the need for ectopic bone formation and allowing rehabilitation with dental implants.
Robustness of modelled ozone exposures and doses Tuovinen, J.-P.; Simpson, D.; Emberson, L. ...
Environmental pollution (1987),
04/2007, Letnik:
146, Številka:
3
Journal Article, Conference Proceeding
Recenzirano
This study evaluates the robustness of the AOT
X and AF
st
Y indices for assessing the ozone-induced risk to vegetation. These indices represent the accumulated concentration and stomatal flux, ...respectively, above a threshold value. The robustness is expressed as the sensitivity to changes in inputs and the uncertainty due to input errors. The input data are taken from a regional-scale chemical transport model. Both indices show increasing sensitivity with increasing threshold values. The sensitivity depends on the threshold and the characteristics of the frequency distribution for concentrations and stomatal fluxes. AF
st
Y appears less sensitive than AOT
X for the thresholds adopted for critical levels. The couplings between concentration gradients and deposition algorithms complicate the assessment of the total uncertainty. For AF
st
Y, the uncertainty due to the modelled stomatal conductance may sometimes increase, but sometimes decrease, the overall uncertainty significantly. In particular, the maximum stomatal conductance plays an important role in determining the uncertainty.
The AF
st
Y index is less sensitive to uncertainties than AOT
X, but depends strongly on the stomatal conductance model.
Modelling stomatal ozone flux across Europe Emberson, L D; Ashmore, M R; Cambridge, H M ...
Environmental pollution (1987),
09/2000, Letnik:
109, Številka:
3
Journal Article
Recenzirano
A model has been developed to estimate stomatal ozone flux across Europe for a number of important species. An initial application of this model is illustrated for two species, wheat and beech. The ...model calculates ozone flux using European Monitoring and Evaluation Programme (EMEP) model ozone concentrations in combination with estimates of the atmospheric, boundary layer and stomatal resistances to ozone transfer. The model simulates the effect of phenology, irradiance, temperature, vapour pressure deficit and soil moisture deficit on stomatal conductance. These species-specific microclimatic parameters are derived from meteorological data provided by the Norwegian Meteorological Institute (DNMI), together with detailed land-use and soil type maps assembled at the Stockholm Environment Institute (SEI). Modelled fluxes are presented as mean monthly flux maps and compared with maps describing equivalent values of AOT40 (accumulated exposure over threshold of 40 ppb or nl l(-1)), highlighting the spatial differences between these two indices. In many cases high ozone fluxes were modelled in association with only moderate AOT40 values. The factors most important in limiting ozone uptake under the model assumptions were vapour pressure deficit (VPD), soil moisture deficit (for Mediterranean regions in particular) and phenology. The limiting effect of VPD on ozone uptake was especially apparent, since high VPDs resulting in stomatal closure tended to co-occur with high ozone concentrations. Although further work is needed to link the ozone uptake and deposition model components, and to validate the model with field measurements, the present results give a clear indication of the possible implications of adopting a flux-based approach for future policy evaluation.
The DO3 SE (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 DO3 SE 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.
Background
Most methods of assessing colonic motility are poorly acceptable to patients. Magnetic resonance imaging (MRI) can monitor gastrointestinal motility and fluid distributions. We predicted ...that a dose of oral polyethylene glycol (PEG) and electrolyte solution would increase ileo‐colonic inflow and stimulate colonic motility. We aimed to investigate the colonic response to distension by oral PEG electrolyte in healthy volunteers (HVs) and to evaluate the effect of single 2 L vs split (2 × 1 L) dosing.
Methods
Twelve HVs received a split dose (1 L the evening before and 1 L on the study day) and another 12 HVs a single dose (2 L on the main study day) of PEG electrolyte. They underwent MRI scans, completed symptom questionnaires, and provided stool samples. Outcomes included small bowel water content, ascending colon motility index, and regional colonic volumes.
Key Results
Small bowel water content increased fourfold from baseline after ingesting both split (p = 0.0010) and single dose (p = 0.0005). The total colonic volume increase from baseline was smaller for the split dose at 35 ± 8% than for the single dose at 102 ± 27%, p = 0.0332. The ascending colon motility index after treatment was twofold higher for the single dose group (p = 0.0103).
Conclusions & Inferences
Ingestion of 1 and 2 L PEG electrolyte solution caused a rapid increase in the small bowel and colonic volumes and a robust rise in colonic motility. The increase in both volumes and motility was dose dependent. Such a challenge, being well‐tolerated, could be a useful way of assessing colonic motility in future studies.
Oral polyethylene glycol (PEG) electrolyte was used as standardized colonic stimulation and magnetic resonance imaging (MRI) was used to monitor fluid distributions and gastrointestinal motility non‐invasively. PEG electrolyte solution increased the small bowel water content fourfold. The size of the colon doubled after dosing and the ascending colon motility index raised markedly, the increase was dose dependent. Such a challenge, being well‐tolerated, could be a useful way of assessing colonic motility in future studies.
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