Simulation of the observed evening transition and nocturnal boundary layers: Single‐column modelling

• Published in: Quarterly journal of the Royal Meteorological Society Vol. 132; no. 614; pp. 61 - 80
• Main Authors: Edwards, J. M., Beare, R. J., Lapworth, A. J.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-01-2006; Wiley
• Subjects: Convection, turbulence, diffusion. Boundary layer structure and dynamics; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology; parametrization; Stable boundary‐layer; United Kingdom; Western Europe; Mid latitude; Synoptic scale; Night; Europe; Atmospheric boundary layer; Observation data; digital simulation; Parameterization; Atmospheric stability; Stable boundary-layer parametrization
• ISSN: 0035-9009; 1477-870X
• DOI: 10.1256/qj.05.63

Observations of the evolution of the atmospheric boundary layer through the evening transition and the early hours of the night are presented. Parallel simulations in a single‐column model are conducted to assess the performance of the parametrization scheme and the sensitivity to vertical resolution. The study is set within the context of a numerical weather‐prediction system and the importance of the synoptic situation is emphasized.
Comparisons are also drawn with an accompanying study describing large‐eddy simulations based on these same data. These show that, when the single‐column model is run with sharp‐tailed stability functions, turbulent diffusion is systematically underestimated in and just above the surface layer, while it is overestimated at greater heights; the parametrized profile of diffusivity is therefore too uniform, causing the temperature profile in the single‐column model to exhibit negative curvature, rather than the positive curvature seen in the observations and in the large‐eddy simulations. Copyright © 2006 Crown copyright