83rd Annual

Thursday, 13 February 2003: 3:44 PM
Observations and conclusions from the surface layer stability transition experiments
Gail-Tirrell Vaucher, Army Research Laboratory, WSMR, NM
Poster PDF (213.4 kB)
The behavior of the atmospheric boundary layer during the transition from a stable nocturnal boundary layer to an unstable daytime boundary layer is not well understood, yet, is of interest to several fields, including chemical and pollutant modeling. Vaucher and Endlich observed a seasonal pattern associated with the Stability Transition timing and local sunrise in 1994 and 1995. In 2001, the Army Research Laboratory pursued a validation of the Stability Transition seasonal pattern, as well as a further transition period characterization, by conducting three specifically timed field experiments. The first and third experiments were executed when a statistically minimum delay between the sunrise and transition (neutral) atmospheric conditions was expected. The second experiment was conducted when a statistically maximum time period between sunrise and transition was forecasted. The results of these experiments validated an evolving Neutral Event Forecasting Model and provided a Eulerian and quasi-Lagrangian perspective on the Nocturnal Stable, Neutral and Day-time Unstable sub-cases. This paper presents the key Experiment observations and conclusions.

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