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Estimates of roughness length from minisonde profiles in the Athabasca oil sands area
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- Author(s) / Creator(s)
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Minisonde data collected in the Athabasca Oil Sands area from 1975 to 1979 were analysed to determine regional values of roughness length (Zo). A rigorous selection re reduced the working data set to a small fraction of the original size. A least squares technique was used to determine from profiles of wind and temperature locally measured near the 50, 100, and 150 m levels. Mean Zo values calculated with allowance for diabatic and displacement height effects ranged from about 8 m downwind of the Syncrude plant site to about 1 m in the Athabasca River valley. Uncertainties in the estimates were of the same magnitude as the mean values. No differences in Zo were found with wind direction. The large values for Zo were attributed primarily to form drag from terrain features in the area during slightly unstable conditions. The study suggested that, where form drag is important, Zo may be stability dependent. An error analysis using reasonable uncertainties for wind speed, balloon height, and temperature gradient measurements showed that probable errors in the estimate of Zo were comparable to the observed variability in Zo.
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- Date created
- 1985
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- Subjects / Keywords
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- Type of Item
- Report
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- License
- This material is provided under educational reproduction permissions included in Alberta Environment and Sustainable Resource Development's Copyright and Disclosure Statement, see terms at http://www.environment.alberta.ca/copyright.html. This Statement requires the following identification: \"The source of the materials is Alberta Environment and Sustainable Resource Development http://www.environment.gov.ab.ca/. The use of these materials by the end user is done without any affiliation with or endorsement by the Government of Alberta. Reliance upon the end user's use of these materials is at the risk of the end user.