| 1. |
- Eliasson, Ingegärd, 1961, et al.
(author)
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Summer nocturnal ozone maxima in Goteborg, Sweden
- 2003
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In: ATMOSPHERIC ENVIRONMENT. - 1352-2310. ; 37:19, s. 2615-2627
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Journal article (peer-reviewed)abstract
- The magnitude and frequency of nocturnal ozone maxima in a high mid-latitude city (Göteborg, Sweden) has been analysed. Nocturnal ozone maxima have been reported from cities in Europe and North America and can be explained by vertical mixing of high ozone concentrations from higher levels or horizontal transportation from rural areas through local and mesoscale wind systems. Data from four summer months (May–August) in 1994 were used to analyse the relative importance of local- and mesoscale wind systems and vertical mixing in Göteborg during clear and calm weather conditions. Results show that nocturnal ozone maxima frequently occur during these conditions, with a magnitude up to 104 μg m−3. The nocturnal ozone maxima were positively correlated to both situations with a well-developed land breeze and situations with vertical mixing. During the period investigated, in total 17 nights with secondary ozone maximum occurred. The majority of the secondary ozone maxima (80%) appeared early in the night, i.e. an ozone increase within the first 3 h after sunset and sometimes even two peaks occurred. Seven of these occasions can be explained by horizontal advection, eight by vertical mixing and five cannot by certainty be explained to be due to horizontal or vertical transportation only. During the measurement period the Swedish guideline of 80 μg m−3 (for 1-h value) was exceeded 55% of the days (i.e. 68 days, 557 h) and 33% of the nights (i.e. 41 nights, 103 h) in the central parts of Göteborg. The results thus show that in Scandinavia nocturnal ozone
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| 2. |
- Svensson, Marie, 1973, et al.
(author)
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A geographical information system model for creating bioclimatic maps - examples from a high, mid-latitude city
- 2003
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In: INTERNATIONAL JOURNAL OF BIOMETEOROLOGY. - 0020-7128. ; 47:2, s. 102-112
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Journal article (peer-reviewed)abstract
- This paper presents a method for creating large-scale bioclimatic maps with the aid of a geographical information system, GIS. Meteorological data are linked with geographical information about land use, elevation and distance to the coast, in order to generate spatial distributions of physiological equivalent temperature, PET. The model combines an air temperature map and a wind map in order to create different zones for which the thermal component is to be calculated. The advantage of the model presented is that it uses generally available information about land use, altitude and distance to the coast. Further, the model uses a GIS application, which makes it non-static. Compared to most other models, a wide range of observations are used as input. Few biometeorological studies have been performed in high-latitude areas. This paper presents bioclimatic maps for the Goteborg urban area, in Sweden, for the month of July. The results show large variations in PET during a clear, calm day at 1200 hours (DeltaT 13.4 degreesC) and during average conditions in July (DeltaT 6.8 degreesC), which gives an indication of the magnitude and the spatial variations within high, midlatitude, urban area in summer. The highest PET values were found in the central built-up areas and the lowest PET values in the coastal and green areas. The model generates valuable information for urban planners and decision makers when planning and constructing new areas for outdoor activities etc. This information is also useful in the fields of health and energy.
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| 3. |
- Thorsson, Sofia, 1972, et al.
(author)
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An intra-urban thermal breeze in Göteborg, Sweden.
- 2003
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In: Theoretical and Applied Climatology. ; 75, s. 93-104
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Journal article (peer-reviewed)abstract
- The existence and character of an intra-urban thermal breeze (IUTB) in the city centre of Goteborg, Sweden was examined. The study was carried out in a 10 ha open area covered with gravel, asphalt and grass, surrounded by narrow street canyons. Measurements included an array of fixed wind and temperature sensors and smoke in the open area; temperature of the surrounding neighbourhood from mobile thermal mapping and fixed temperature sensors; standard climate measurements from four automatic weather stations in and around Goteborg. The results based on sixteen field surveys performed between December 1998 and March 2000 showed that the open urban area might generate a special type of IUTB under certain conditions. The IUTB was shown to be a rare nocturnal winter phenomenon developing during clear and calm weather conditions, with snow covered ground, strong ground based inversions and high stability (Ri(b) > 1). The most important driving forces for the generation of an IUTB were large intra-urban horizontal air temperature differences and strong atmospheric stability which led to decoupling of the canopy layer atmosphere from wind flow aloft. In order to estimate the physical principles underlying an IUTB of this type a simple 1.5-dimensional model was devised. Results indicated that the horizontal intra-urban air temperature difference recorded in Goteborg was enough to develop an IUTB.
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| 4. |
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| 5. |
- Thorsson, Sofia, 1972, et al.
(author)
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Thermal bioclimatic conditions and patterns of behaviour in an urban park in Goteborg, Sweden
- 2004
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In: International Journal of Biometeorology. - : Springer Science and Business Media LLC. - 0020-7128 .- 1432-1254. ; 48:3, s. 149-156
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Journal article (peer-reviewed)abstract
- People in urban areas frequently use parks for recreation and outdoor activities. Owing to the complexity of the outdoor environment, there have only been a few attempts to understand the effect of the thermal environment on people's use of outdoor spaces. This paper therefore seeks to determine the relationship between the thermal environment, park use and behavioural patterns in an urban area of Sweden. The methods used include structured interviews, unobtrusive observations of the naturally occurring behaviour and simultaneous measurements of thermal comfort variables, i.e., air temperature, air humidity, wind speed and global radiation. The thermal environment is investigated through the mean radiant temperature (T-mrt) and the predicted mean vote (PMV) index. The outcome is compared to the subjective behaviour and thermal sensation of the interviewees. It is found that the thermal environment, access and design are important factors in the use of the park. In order to continue to use the park when the thermal conditions become too cold or too hot for comfort, people improve their comfort conditions by modifying their clothing and by choosing the most supportive thermal opportunities available within the place. The study also shows that psychological aspects such as time of exposure, expectations, experience and perceived control may influence the subjective assessment. Comparison between the thermal sensation of the interviewees and the thermal sensation assessed by the PMV index indicates that steady-state models such as the PMV index may not be appropriate for the assessment of short-term outdoor thermal comfort, mainly because they are unable to analyse transient exposure.
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