Categorization of nocturnal drainage flows within the Brush Creek valley in western Colorado and the variability of sigma theta in complex terrain
The monthly frequencies of nocturnal drainage flows in the Brush Creek valley were estimated over the period August 1982 to January 1985 for the purpose of evaluating the representativeness of the drainage flows observed during a few intensive study periods. These estimates were made on the basis of data from three short meteorological towers situated in the valley. The highest frequencies were observed during the June to October timeframes: 30 to 40% during 1983 and 10 to 30% during 1984. Of the ten experimental nights when intensive investigations were conducted within the Brush Creek valley, seven were during strong drainage flow periods and three were during weaker drainage flow periods. The variability of sigma theta in complex terrain areas was investigated since this parameter is often used to estimate diffusion of pollutants. Measurements made during strong drainage flow periods within two valleys in The Geysers geothermal area in northern California and within the Brush Creek valley yielded hourly-averaged values that varied from a few degrees to a little over one hundred degrees at each measurement site. The median values typically ranged from 15{sup 0} to 40{sup 0}. Generally, the highest values were acquired at measurement sites situated on the valley floor; the lowest values on the ridges; and intermediate values along the slopes. This ordering may be due to the winds generally being stronger over the ridges than within the valley, since there is weak evidence for an inverse relationship between the median wind speeds and sigma theta values, even though this relationship was not in evidence between the individual measurements. 3 refs., 9 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5754118
- Report Number(s):
- UCID-20414; ON: DE85011291
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SURFACE AIR
DRAINAGE
COMPLEX TERRAIN
EARTH ATMOSPHERE
EXPERIMENTAL DATA
FLUID FLOW
GEYSERS GEOTHERMAL FIELD
NOCTURNAL VARIATIONS
AIR
DATA
FLUIDS
GASES
GEOTHERMAL FIELDS
INFORMATION
NUMERICAL DATA
VARIATIONS
Geothermal Legacy
500100* - Environment
Atmospheric- Basic Studies- (-1989)