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| 2. |
- Karlsson, Per Erik, et al.
(författare)
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En ekonomisk utvärdering av inverkan av marknära ozon på växtligheten i Sverige i relation till föreslagna miljömål
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- De ekonomiska kostnader som kan uppstå genom inverkan av ozon nära marken på produktionen i jord- och skogsbruk i Sverige har utvärderats. Beräkningarna har utgått från fyra olika scenarier för ozonförekomst: 1. Nuvarande ozonbelastning. 2. en ozonbelastning motsvarande ett förslag till kortsiktigt målvärde inom miljömålet Frisk luft, att ozonbelastningen inte skall överskrida AOT40 20 000 µg m-3 till år 2015. 3. En ozonbelastning motsvarande ett förslag till långsiktigt målvärde inom miljömålet Frisk luft, att ozonbelastningen inte skall överskrida AOT30 18 000 µg m-3. 4. En prognos för framtida ozonförekomst för år 2020 baserat på AOT40. skillnaden i de årliga ekonomiska kostnaderna mellan nuvarande ozonbelastning och scenariot för år 2020, 150 MSEK, kan ses som en grov uppskattning av den ekonomiska vinst som uppstår vad gäller inverkan av ozon på växtligheten i Sverige, om det föreslagna kortsiktiga målvärdet klaras över hela landets areal.
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| 3. |
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| 4. |
- Karlsson, Per Erik, 1957, et al.
(författare)
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Ozone concentration gradients and wind conditions in Norway spruce (Picea abies) forests in Sweden
- 2006
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 40:9, s. 1610-1618
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Tidskriftsartikel (refereegranskat)abstract
- Ozone concentrations and wind conditions were measured at different heights above ground inside two different Norway spruce forest canopies in Sweden and compared to those outside or above the forests. Compared to high above ground outside or above the canopies, the ozone concentrations inside the Norway spruce forests were reduced 3-8% during mid-day and 10-40% during nighttime. Daylight Accumulated exposure Over a Threshold 40ppb (AOT40) was reduced 15-45% inside as compared to outside the forest. The horizontal concentration differences between inside and outside the forest were in the order of 3-4%, independently of the height above ground. The ozone concentration difference inside and outside the forest depended on the air turbulence as well as the horizontal wind speed inside the forest. It also depended on the distance to the forest edge in relation to the wind direction. The ozone concentration differences inside and outside the Norway spruce forests were explained by the differences in the rate of dry deposition in relation to the rate of replacement of ozone from higher air layers or by the horizontal wind going into the forest. (c) 2005 Elsevier Ltd. All rights reserved.
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| 5. |
- Pleijel, Håkan, 1958, et al.
(författare)
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Differential ozone sensitivity in an old and a modem Swedish wheat cultivar - grain yield and quality, leaf chlorophyll and stomatal conductance
- 2006
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Ingår i: Environmental and Experimental Botany. - : Elsevier BV. - 0098-8472. ; 56:1, s. 63-71
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Tidskriftsartikel (refereegranskat)abstract
- Field-grown crops of one modem ('Dragon') and one 100-year old ('Lantvete') wheat (Triticum aestivum L.) cultivar were exposed to charcoal-filtered air (CF) or non-filtered air plus additional ozone (NF+) in open-top chambers (n = 6). Ambient air plots (11 = 3) were used to monitor the effects of the chamber enclosure. Quantitative (ear weight, harvest index and 1000-grain weight), as well as qualitative (grain concentration of N. P. K, Ca, Mg, Cd), aspects of crop yield were studied. In addition, the chlorophyll content of the top leaf was followed during the 10-week-long ozone exposure and flag leaf stomatal conductance was monitored. Ear weight was negatively affected by ozone. The effect was smaller in the lower yielding 'Lantvete' compared to the modem cultivar 'Dragon'. A similar ozone effect was found for the harvest index and 1000-grain weight. The difference between cultivars was small for 1000-grain weight, with harvest index significantly lower in 'Lantvete' compared with 'Dragon'. The crude protein concentration of the grain was higher in 'Lantvete', and was enhanced by ozone exposure. No significant treatment or cultivar effects were observed on grain Ca and Cd concentrations, but the greatest chamber effect was on Cd, which was considerably higher in grain from treatment chambers compared with ambient air (possibly due to the higher rate of transpiration in the plants enclosed in the chambers). There were strong differences with respect to grain P, K and Mg concentration between cultivars; 'Lantvete' exhibiting higher concentrations than 'Dragon' in all cases, apart from K. Weak, but significant, increases in grain P, K and Mg concentrations were evident in O-3-treated plants. The chlorophyll concentration of the flag leaf was negatively affected by ozone exposure after approximately I month, but chlorophyll content declined faster in 'Dragon' than 'Lantvete'. Flag leaf chlorophyll concentration was significantly lower in 'Lantvete' compared with 'Dragon' before onset of ozone effects in NF+ and during most of the experiment in CF. Stomatal conductance was also significantly lower in 'Lantvete' than in 'Dragon'. The most important conclusion drawn from the present study is that the 'older' cultivar, 'Lantvete', was less affected by ozone than the modem, bred cultivar, 'Dragon'. This observation might to a large extent be explained by the higher stomatal conductance exhibited by the modern wheat cultivar. The result is consistent with earlier investigations for Greek wheat cultivars, and suggests that the findings reported by others, based on vegetative growth, may extend to grain yield. Growth dilution effects (i.e. the lower observed concentration of an element at higher biomass yield) may explain observed differences between cultivars, and between ozone treatments, in the level of various elements, except for potassium. (c) 2005 Elsevier B.V. All rights reserved.
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| 6. |
- Sundberg, Jenny, 1978, et al.
(författare)
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Evaluation of the EMEP photo-oxidant model using ozone and meteorological data from Östad, south-west Sweden, for three growing seasons
- 2006
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Ingår i: Conference: Atmospheric Chemistry at the Interfaces, Joint IGAC/CACGP/WMO Symposium, Cape Town, 18-22 September 2006.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study aimed to evaluate the EMEP photooxidant model by using observations of ozone, air temperature, vapor pressure deficit (VPD) and solar radiation from Östad (Sweden) during three growing seasons, 1997, 1999 and 2000. Also, functions used by the EMEP model to estimate the influences by temperature, VPD and solar radiation on stomatal conductance of crops were applied to observed and modeled data to evaluate the model prediction of stomatal conductance. The results indicated good agreement between model and observations of ozone during daytime, but the nocturnal ozone concentration dropped considerably lower at Östad compared to EMEP model predictions, on average 10 nmol mol-1. The EMEP model tended to overestimate the temperature compared to Östad, especially during the night (3-4°C on average). Large local cooling at night at the monitoring site promoted the generation of temperature inversions and indicated stable atmospheric conditions, which explained the lower nocturnal ozone and temperature compared to the EMEP grid (50*50 km2) values. VPD was overestimated, partly due to overestimation of temperature. The model predicted influence by the meteorological variables on stomatal conductance correlated strongly with predictions based on observed data. Important conclusions from the study were that the EMEP model output correlated well with observed ozone concentration and meteorology at Östad. The differences found were to a large extent due to the specific local climatological conditions at the site, where nocturnal temperature inversions were strong. The synoptic weather situation influenced the agreement between model and observations. Anti-cyclonic weather situations strengthened the differences in local climate between sites within the grid (shown in an earlier study), which led to differences in ozone concentration. During cyclonic weather situations all site specific differences leveled out and the agreement between model and observations was very high. This emphasizes the importance of considering local climate on monitoring sites when evaluating regional air pollution models.
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| 7. |
- Sundberg, Jenny, 1978, et al.
(författare)
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NO, NO2 and O3 concentrations in the polluted urban landscape in comparison with a rooftop monitoring site and a rural site - influence of meteorology
- 2006
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Ingår i: Sixth International conference on urban climate, 12-16 June 2006, Göteborg, Sweden. ; , s. 777-780
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Measurements of NO, NO2 and O3 were performed in Göteborg, Sweden, during the GÖTE 2005 measurement campaign. The aim was to evaluate the variation of pollutant concentrations in the urban landscape in relation to urban air quality monitoring stations and meteorology. Important conclusions were that the pollutant concentrations varied substantially in the urban landscape and that wind speed strongly influenced pollutant concentrations and pollutant gradients. Higher wind speeds act to dilute NO2 due to stronger dispersion, but also lead to an enhanced vertical transport of O3, which produces NO2 through oxidation of NO. The latter effect was strongest at the more polluted sites, while the first effect was more important at the less polluted sites.
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| 8. |
- Sundberg, Jenny, 1978, et al.
(författare)
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Variation in ozone concentration in relation to local climate in south-west Sweden
- 2006
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Ingår i: Water Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 173:1-4, s. 339-354
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Tidskriftsartikel (refereegranskat)abstract
- Ozone (O-3) concentration and air temperature/relative humidity were monitored using diffusive samplers (weekly, 3 m above ground) and Tinytag loggers (10 min sampling, 1 m above ground, self-ventilating radiation shields), respectively, in the forested landscape of south-west Sweden, 40 km north-east of Gothenburg. Two forest sites were included, one at a hilltop (175 m a.s.l.), and one in a nearby (similar to 1 km) valley (110 m a.s.l.). In addition, a valley site (similar to 3 km from the forest sites, 60 m a.s.l.) in an agricultural landscape was included, where ozone was measured using both a UV-based monitor and diffusive sampling. At the agricultural site measurements of temperature and relative humidity were made using a radiation shield with forced ventilation and with Tinytags, as on the forest sites, in addition to observations of wind speed and the vertical temperature gradient. Furthermore, comparison with O-3 concentrations at urban and coastal sites in the region was made. The temperature dependent, systematic error of using a self-ventilating radiation shield was estimated and corrected for. It was found that the elevated forested site experienced higher O-3 concentrations and lower evening cooling rates in calm situations as compared to the forest site in the valley and in particular as compared to the agricultural site. This can be explained by a stronger coupling with the planetary boundary layer at the elevated site and more pronounced night-inversions at the valley sites. The difference in weekly O-3 concentration between the two forested sites was correlated with the difference in average minimum night-time temperature. The coastal site had the highest ozone concentrations, related largely, but not fully, to higher night-time O-3 concentrations. The urban site showed a depression in O-3 concentration associated with the combination of large NO emissions and slow air mixing during the morning traffic rush hours.
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| 9. |
- Uddling, Johan, 1972, et al.
(författare)
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Changes in stomatal conductance and net photosynthesis during phenological development in spring wheat: implications for gas exchange modelling
- 2006
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Ingår i: International Journal of Biometeorology. - : Springer Science and Business Media LLC. - 0020-7128 .- 1432-1254. ; 51:1, s. 37-48
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Tidskriftsartikel (refereegranskat)abstract
- Gas exchange was measured from 1 month before the onset of anthesis until the end of grain filling in field-grown spring wheat, Triticum aestivum L., cv. Vinjett, in southern Sweden. Two g (s) models were parameterised using these data: one Jarvis-type multiplicative g (s) model (J-model), and one combined stomatal-photosynthesis model (L-model). In addition, the multiplicative g (s) model parameterisation for wheat used within the European Monitoring and Evaluation Programme (EMEP-model) was tested and evaluated. The J-model performed well (R-2=0.77), with no systematic pattern of the residuals plotted against the driving variables. The L-model explained a larger proportion of the variation in g (s) data when observations of A (n) were used as input data (R-2=0.71) compared to when A (n) was modelled (R-2=0.53). In both cases there was a systematic model failure, with g (s) being over- and underestimated before and after anthesis, respectively. This pattern was caused by the non-parallel changes in g (s) and A (n) during plant phenological development, with A (n) both peaking and starting to decline earlier as compared to g (s) . The EMEP-model accounted for 41% of the variation in g (s) data, with g (s) being underestimated after anthesis. We conclude that, under the climatic conditions prevailing in southern Scandinavia, the performance of the combined stomatal-photosynthesis approach is hampered by the non-parallel changes in g (s) and A (n), and that the phenology function of the EMEP-model, having a sharp local maximum at anthesis, should be replaced by a function with a broad non-limiting period after anthesis.
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