Comparison of wind spectra from spatially averaged and point measurements in complex terrain

Conference · Mon Sep 01 04:00:00 EDT 1980

OSTI ID:6901643

Porch, W M

Results are reported for two experiments in complex terrain where a single light path was used across a valley. These experiments were conducted in two regions of California during the same month on different years. The regions differed significantly in their meteorological regimes. The first experiment was conducted across a very windy pass (Patterson Pass) east of Lawrence Livermore National Laboratory (LLNL). The second experiment was conducted in a relatively low wind location (Anderson Creek) influenced by drainage wind transport of effluent from geothermal energy wells. This second study was part of the Atmospheric Studies in Complex Terrain (ASCOT). The two studies were conducted in July 1977 (Patterson Pass) and 1979 (ASCOT). Comparison of the normalized autospectral densities of the spatially averaged and point wind measurements showed similar behavior for periods longer than four hours. For periods shorter than four hours the spectra diverge with different slopes for both region's data. This divergence at this relatively low frequency was found to be associated more with wind direction than wind speed changes. This fact would be consistent with increased deviation in wind direction in complex terrain at high frequencies, drawing energy from lower frequency variability for point wind measurements. This is not reflected in the spacially averaged data over several hundred meters. Other explanations exist, but in any case, spectral comparison of point and spacially averaged wind points to wind speed and direction interaction which is peculiar to complex terrain.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore National Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6901643
• Report Number(s): UCRL-84546; ASCOT-80-8; CONF-810306-4
• Country of Publication: United States
• Language: English

Related Subjects

500100* -- Environment
Atmospheric-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
CALIFORNIA
COMPARATIVE EVALUATIONS
DIFFUSION
ENVIRONMENTAL TRANSPORT
MASS TRANSFER
METEOROLOGY
MOUNTAINS
NORTH AMERICA
POINT SOURCES
POLLUTION
RADIATION SOURCES
SPECTRA
TIME DEPENDENCE
USA
VALLEYS
VELOCITY
WESTERN REGION
WIND