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- Davis, J.L, et al.
(författare)
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Geodesy by radio interferometry: Effects of atmospheric modeling errors on estimates of baseline length
- 1985
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Ingår i: Radio Science. - 0048-6604 .- 1944-799X. ; 20:6, s. 1593-1607
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of very long baseline interferometry data indicates that systematic errors in prior estimatesof baseline length, of order 5 cm for ~8000-km baselines, were due primarily to mismodeling of theelectrical path length of the troposphere and mesosphere ("atmospheric delay"). Here we discussobservational evidence for the existence of such errors in the previously used models for the atmosphericdelay and develop a new "mapping" function for the elevation angle dependence of this delay. Thedelay predicted by this new mapping function differs from ray trace results by less than ~5 mm, at allelevations down to 5° elevation, and introduces errors into the estimates of baseline length of •
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| 5. |
- Elgered, Gunnar, 1955, et al.
(författare)
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Measurements of atmospheric water vapor with microwave radiometry
- 1982
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Ingår i: Radio Science. - 0048-6604 .- 1944-799X. ; 17:5, s. 1258-1264
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Tidskriftsartikel (refereegranskat)abstract
- A dual-channel, ground-based microwave radiometer, working at the frequencies 21.0 and 31.4 GHz, an infrared spectral hygrometer, and radiosondes have been used for comparative measurements of the integrated amount of precipitable water vapor in the atmosphere over a period with zenith water vapor contents varying between 6 and 26 mm. The microwave radiometer was found to give comparable or better formal accuracy than the radiosondes, the absolute accuracy of which is believed to be about 1 mm. The rms difference of the integrated amount of water vapor in the zenith direction measured with the microwave radiometer and with radiosondes was 1.2 mm for all data, and 0.8 mm for a selected group of good weather data. These are lower formal errors than previously reported. It is shown that the simplified relation between the radiometer antenna termperatures and the integrated amount of water vapor in this case contributes with a formal error of about 0.3 mm. It is suggested that mean ground weather data can be used to adapt this relation to other sites and seasons.
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| 6. |
- Petersson, Göran, 1941
(författare)
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Ambient hydrocarbons from motor-car assembly plants in Scandinavia
- 1982
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Ingår i: Environmental Pollution (Series B). ; 4, s. 207-217
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Tidskriftsartikel (refereegranskat)abstract
- About 50 air-polluting hydrocarbons were determined in emissions from the Volvo and Saab motor-car plants. The sampling technique used was based on the Tenax GC adsorbent. Thermal desorption and glass capillary gas chromatography was used for the analysis. At a downwind distance of about 1 km, concentrations about 100 times higher than regional levels were recorded. The emissions constitute potential ecological and health hazards and a reduction of quantities and complexity is urgent.
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| 10. |
- Petersson, Göran, 1941
(författare)
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Exposition för bilavgaser
- 1980
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Ingår i: Barnets totala trafikmiljö; NU 1980:16. - 9170525072 ; , s. 81-85
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Slutsatser av ett par års haltmätningar för avgasspecifika kolväten i tätortsmiljöer presenterades. Konstruerade diagram visades över hur expositionen typiskt varierar dels under en kort promenad utefter en gata och dels under ett helt dygn. Kunskaper om typiska haltskillnader mellan olika närmiljöer ger underlag både för trafikplanering och för den som själv omgående vill minska sin exposition.
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