On the Structure and Adjustment of Inversion-Capped Neutral Atmospheric Boundary-Layer Flows: Large-Eddy Simulation Study

Jesper Grønnegaard Pedersen, Sven-Erik Gryning, Mark C. Kelly

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    A range of large-eddy simulations, with differing free atmosphere stratification and zero or slightly positive surface heat flux, is investigated to improve understanding of the neutral and near-neutral, inversion-capped, horizontally homogeneous, barotropic atmospheric boundary layer with emphasis on the upper region. We find that an adjustment time of at least 16 h is needed for the simulated flow to reach a quasi-steady state. The boundary layer continues to grow, but at a slow rate that changes little after 8 h of simulation time. A common feature of the neutral simulations is the development of a super-geostrophic jet near the top of the boundary layer. The analytical wind-shear models included do not account for such a jet, and the best agreement with simulated wind shear is seen in cases with weak stratification above the boundary layer. Increasing the surface heat flux decreases the magnitude and vertical extent of the jet and leads to better agreement between analytical and simulated wind-speed profiles. Over a range of different inversion strengths and surface heat fluxes, we also find good agreement between the performed simulations and models of the equilibrium boundary-layer height, and of the budget of turbulent kinetic energy integrated across the boundary layer.
    Original languageEnglish
    JournalBoundary-Layer Meteorology
    Volume153
    Issue number1
    Pages (from-to)43-62
    ISSN0006-8314
    DOIs
    Publication statusPublished - 2014

    Keywords

    • HASH(0x56f8228)
    • Inversion strength
    • Large-eddy simulation
    • Neutral atmospheric boundary layer
    • Wind profiles

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