Experimental and model transport and diffusion studies in complex terrain with emphasis on tracer studies

• Published in: Boundary - layer meteorology 1984-01, Vol.30 (1-4), p.333-350
• Main Authors: DICKERSON, M. H, FOSTER, K. T, GUDIKSEN, P. H
• Format: Article
• Language: English
• Subjects: Convection, turbulence, diffusion. Boundary layer structure and dynamics; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology
• ISSN: 0006-8314; 1573-1472
• DOI: 10.1007/BF00121960

The U.S. Department of Energy (DOE) Atmospheric Studies in the Complex Terrain (ASCOT) program began in the fall of 1978 as a multiple DOE and other Federal Laboratory program devoted to developing a better physical understanding of atmospheric boundary layer flows in areas of complex terrain. The first technical challenge undertaken by the program was an investigation of atmospheric boundary layer phenomena associated with the development, continuation, and breakup of nocturnal drainage wind flows. The authors discuss the general objectives of the program and focus on results from a major field experiment conducted in 1980 in the Geysers area of northern California. Specifically, results from measurements of simultaneous tracer releases are compared with calculations from a mass-consistent wind field model coupled to a particle-in-cell transport and diffusion model. Results of these comparisons show that model calculations agree with measurements within a factor of 5 similar to 50% of the time. Part of the difficulty faced by the models in these comparison studies is associated with large variabilities between measurements made by samplers located one or two Delta x apart when compared to the resolution of the models. Space and time averaging improves the comparisons considerably, although the design of the field experiment did not permit the determination of optimum spatial and temporal averages.