Boundary-Layer Meteorology

, Volume 104, Issue 3, pp 371–379

On Integral Measures Of The Neutral Barotropic Planetary Boundary Layer


  • S. S. Zilitinkevich
    • Department of Earth Sciences, MeteorologyUppsala University
  • I. N. Esau
    • Department of Earth Sciences, MeteorologyUppsala University

DOI: 10.1023/A:1016540808958

Cite this article as:
Zilitinkevich, S.S. & Esau, I.N. Boundary-Layer Meteorology (2002) 104: 371. doi:10.1023/A:1016540808958


Two types of neutral planetary boundary layer (PBL) are distinguished:truly neutral – developed against a neutrally stratified free flow, and conventionally neutral – developed against a background stable stratification. Atmospheric PBLs treated asneutral are almost always conventionally neutral. Theoretical reasoning and results from large-eddy simulation (LES) show that A and B coefficients of the Rossby-number similarity theory are not constants. The same is true for thecoefficient Ch in the Rossby–Montgomery formula for the neutral boundary-layer depth h = Chu*/|f|, where u* is the friction velocity. Contrary to classical ideas, A, B and Ch depend on the ratio μN≡ N/|f| of the free-flow Brunt–V*auml;isäl ä frequency N to the absolute value of the Coriolis parameter |f|. This new development can explain why atmospheric and LES estimates of A, B and Ch appear inconsistent. It results from neglecting the fact that atmospheric data for μN ∼ 102 were compared with LES data for μN = 0, violating an obvious requirement of similarity with respect to μN.

Boundary-layer depthFree-flow stabilityNeutral boundary layerResistance law

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© Kluwer Academic Publishers 2002