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| 2. |
- Hageback, Johanna, et al.
(författare)
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Climate variability and land-use change in Danangou watershed, China : Examples of small-scale farmers' adaptation
- 2005
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Ingår i: Climatic Change. - : Springer Science and Business Media LLC. - 0165-0009 .- 1573-1480. ; 72:1-2, s. 189-212
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Tidskriftsartikel (refereegranskat)abstract
- With global concern on climate change impacts, developing countries are given special attention due their susceptibility. In this paper, change and variability in climate, land use and farmers’ perception, adaptation and response to change are examined in Danangou watershed in the Chinese Loess Plateau. The first focus is to look at how climate data recorded at meteorological stations recently have evolved, and how farmers perceived these changes. Further, we want to see how the farmers respond and adapt to climate variability and what the resulting impact on land use is. Finally, other factors causing change in land use are considered. Local precipitation and temperature instrumental data and interview data from farmers were used. The instrumental data shows that the climate is getting warmer and drier, the latter despite large interannual variability. The trend is seen on the local and regional level. Farmers’ perception of climatic variability corresponds well with the data record. During the last 20 years, the farmers have become less dependent on agriculture by adopting a more diversified livelihood. This adaptation makes them less vulnerable to climate variability. It was found that government policies and reforms had a stronger influence on land use than climate variability. Small-scale farmers should therefore be considered as adaptive to changing situations, planned and non-consciously planned.
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- Karlsson, Per Erik, 1957, et al.
(författare)
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Increasing risk for negative ozone impacts on vegetation in northern Sweden
- 2007
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Ingår i: Environmental Pollution. ; 150, s. 96-106
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Tidskriftsartikel (refereegranskat)abstract
- Trends were found for increasing surface ozone concentrations during AprileSeptember in northern Sweden over the period 1990e2006 as well as for an earlier onset of vegetation growing season. The highest ozone concentrations in northern Sweden occurred in April and the ozone concentrations in April showed a strong increasing trend. A model simulation of ozone flux for Norway spruce indicated that the provisional ozone flux based critical level for forests in Europe is exceeded in northern Sweden. Future climate change would have counteracting effects on the stomatal conductance and needle ozone uptake, mediated on the one hand by direct effect of increasing air temperatures and on the other through increasing water vapour pressure difference between the needles and air. Thus, there is a substantial and increasing risk for negative impacts of ozone on vegetation in northern Sweden, related mainly to increasing ozone concentrations and an earlier onset of the growing season.
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- 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 and exposure in relation to local climate in south-west Sweden
- 2005
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Ingår i: Hunova I (Ed) Acid Rian 2005, 7th International Conference on Acid Deposition, Conference Abstracts..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ozone concentration and temperature/relative humidity were monitored using passive diffusion sampling (weekly at 3 m height) and TinyTag sensors/loggers (10 minute sampling at 1 and 5 m height in self-ventilating radiation shields), respectively in the forested landscape of south-west Sweden, 50 km north-east of Göteborg,. Two forested sites were included, one situated at the top of a hill (175 m a.s.l.), and one in a nearby valley (110 m a.s.l.). In addition, a site located in an agricultural landscape was included, where ozone was measured using a UV-based monitor and measurements of temperature and relative humidity were made using a radiation shield with forced ventilation. Furthermore, a comparison with ozone concentrations at an urban and a coastal monitoring site in the region were made. It was concluded from the parallel measurements at the agricultural site that the diffusion samplers predicted the weekly ozone concentration with high accuracy. The temperature dependent systematic error of using a self-ventilating radiation shield, overestimating higher temperatures, was estimated and corrected. It was found that the elevated forested site experienced considerably higher ozone concentrations than the forest site in the valley and the agricultural site. This can be explained by stronger coupling with the boundary layer at the elevated site and more pronounced night-inversions at the valley and agricultural sites. The forested area of the interior of south-west Sweden was concluded to have lower concentrations, especially during the night, compared to the coastal site, while the comparison with the urban site revealed a more complex pattern. Climate data was used to asses the risk for plant ozone uptake.
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| 9. |
- 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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