Evaluation of a mesoscale atmospheric dispersion modeling system with observations from the 1980 Great Plains mesoscale tracer field experiment. Part I: Datasets and meterological simulations

Journal Article · Fri Mar 01 04:00:00 EST 1996 · Journal of Applied Meteorology

DOI:https://doi.org/10.1175/1520-0450(1996)035<0281:EOAMAD>2.0.CO;2· OSTI ID:274059

Moran, M D; Pielke, R A ^[1]

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1. Colorado State Univ., Fort Collins, CO (United States)

A mesoscale atmospheric dispersion (MAD) numerical modeling system, consisting of a mesoscale meteorological model coupled to a mesoscale Lagrangian particle dispersion model, was used to simulate transport and diffusion of a perfluorocarbon tracer-gas cloud for a surface release during the July 1980 Great Plains mesoscale tracer field experiment. Ground-level concentration (GLC) measurements taken downwind of the release site up to three days after the tracer release were available for comparison. Quantitative measures of significant dispersion characteristics obtained from analysis of the tracer cloud`s moving GLC {open_quotes}footprint{close_quotes} were used to evaluate the simulation of the MAD case. MAD is more dependent on the spatial and temporal structure of the transport wind field than is short-range atmospheric dispersion. For the tracer experiment, the observations suggest that the nocturnal low-level jet played an important role in transporting and deforming the tracer cloud. Ten two- and three-dimensional numerical meteorological experiments were devised to investigate the relative contributions of topography, other surface inhomogeneities, atmospheric baroclinicity, synoptic-scale flow evolution, and meteorological model initialization time to the structure and evolution of the low-level mesoscale flow field and thus to MAD. Results from the meteorological simulations are compared in this paper. The predicted wind fields display significant differences, which give rise in turn to significant differences in predicted low-level transport. The presence of an oscillatory ageostrophic component in the observed synoptic low-level winds for this case is shown to complicate initialization of the meteorological model considerably and is the likely cause of directional errors in the predicted mean tracer transport. A companion paper describes the results from the associated dispersion simulations. 76 refs., 13 figs., 6 tabs.

• OSTI ID: 274059
• Journal Information: Journal of Applied Meteorology, Journal Name: Journal of Applied Meteorology Journal Issue: 3 Vol. 35; ISSN 0894-8763; ISSN JOAMEZ
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR-BIOSPHERE INTERACTIONS
DISPERSIONS
LONG-RANGE TRANSPORT
MATHEMATICAL MODELS
METEOROLOGY
OKLAHOMA
PARTICULATES
SIMULATION