| 1. |
- Axelsson, H, et al.
(författare)
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Differential Optical Absorption Spectroscopy (DOAS) Measurements of Ozone in the 280--290 nm Wavelength Region
- 1990
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Ingår i: Applied Spectroscopy. - : SAGE Publications. - 1943-3530 .- 0003-7028. ; 44:10, s. 1654-1658
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Tidskriftsartikel (refereegranskat)abstract
- The differential absorption structure of the ozone spectrum between 250 and 330 nm has been investigated in order to determine the optimal wavelength region to be utilized for active differential optical absorption spectroscopy (DOAS) measurements. Considering aspects of atmospheric attenuation and interference from other species as well as the magnitude of the differential absorption cross section, an interval around 283 nm was found to be a good candidate for this application. This result was also verified during 12 months of continuous ozone monitoring in an urban environment.
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| 2. |
- Edner, H, et al.
(författare)
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Atmospheric Mercury Mapping In A Cinnabar Mining Area
- 1993
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Ingår i: Science of the Total Environment. - 1879-1026. ; 133:1-2, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- A mobile differential absorption lidar system was used in conjunction with point monitors to study the spatial and temporal distribution of atomic mercury in the atmosphere around an abandoned mercury mine at Abbadia S. Salvatore, Italy. The use of the remote sensing technique allows a fast coverage of large areas both horizontally and vertically with a good temporal resolution. Concentrations exceeding 1000 ng/m3 were measured close to the distillation plant and considerably elevated values also were evident above deposits of roasted cinnabar. Vertical gradients of the mercury concentration in air were established. These showed a very pronounced decrease a few centimeters above the ground.
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| 3. |
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| 4. |
- Edner, H, et al.
(författare)
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Differential Absorption Lidar Mapping of Atmospheric Atomic Mercury In Italian Geothermal Fields
- 1992
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Ingår i: Journal of Geophysical Research. - 2156-2202. ; 97:D4, s. 3779-3786
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Tidskriftsartikel (refereegranskat)abstract
- Results from extensive lidar measurements on atmospheric atomic mercury in Italian geothermal fields are reported. A mobile differential absorption lidar system operating on the 254-nm mercury resonance line with a measuring range of about 1 km was used in mineralized as well as nonmineralized areas. Measurements were performed at geothermal power stations and in an unexploited field with natural surface geothermic manifestations. Atomic mercury concentrations ranging from 2 to 1000 ng/m3 were mapped. The high Italian geothermal mercury concentrations are in strong contrast to the recent lidar finding of the absence of atomic mercury in Icelandic geothermal fields.
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| 5. |
- Edner, H, et al.
(författare)
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Differential Optical-absorption Spectroscopy (doas) System For Urban Atmospheric-pollution Monitoring
- 1993
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Ingår i: Optical Society of America. Journal B: Optical Physics. - 0740-3224. ; 32:3, s. 327-333
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Tidskriftsartikel (refereegranskat)abstract
- We describe a fully computer-controlled differential optical absorption spectroscopy system for atmospheric air pollution monitoring. A receiving optical telescope can sequentially tune in to light beams from a number of distant high-pressure Xe lamp light sources to cover the area of a medium-sized city. A beam-finding servosystem and automatic gain control permit unattended long-time monitoring. Using an astronomical code, we can also search and track celestial sources. Selected wavelength regions are rapidly and repetitively swept by a monochromator to sensitively record the atmospheric absorption spectrum while avoiding the detrimental effects of atmospheric turbulence. By computer fitting to stored laboratory spectra, we can evaluate the path-averaged concentration of a number of important pollutants such as NO2, SO2, and O3. A measurement of NH3 and NO close to the UV limit is also demonstrated.
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| 6. |
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| 7. |
- Edner, H, et al.
(författare)
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Fluorescence Lidar Multicolor Imaging of Vegetation
- 1994
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Ingår i: Optical Society of America. Journal B: Optical Physics. - 0740-3224. ; 33:13, s. 2471-2479
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Tidskriftsartikel (refereegranskat)abstract
- Multicolor imaging of vegetation fluorescence following laser excitation is reported for distances of 50 m. A mobile laser-radar system equipped with a Nd:YAG laser transmitter and a 40-cm-diameter telescope was utilized. The laser light was Raman shifted to 397 nm with pulse energies of approximately 30 mJ. An image-intensified CCD camera with a specially designed split-mirror Cassegrainian telescope was utilized for the simultaneous recording of fluorescence images of leaves and branches in four different spectral bands. Additionally, fluorescence spectra at selected points within the detection area were measured with an image-intensified diode array system. Image processing permits extraction of information related to the physiological status of the vegetation and might prove useful in forest decline research.
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| 8. |
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| 9. |
- Edner, H, et al.
(författare)
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Lidar Measurements of Atmospheric Mercury
- 1991
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Ingår i: Water, Air and Soil Pollution. - 1573-2932. ; 56, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- Mercury is the only atmospheric pollutant that is present in the atmosphere in atomic form. The optical resonance line at 254 nm can be used for absorption measurements using different optical remote sensing techniques. Range-resolved Hg mapping can be performed using the differential absorption lidar (DIAL) technique. We have used the lidar technique both for mapping of industrial plumes and for background concentration measurements. Our studies also include Hg of geophysical origin.
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| 10. |
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