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Large-Eddy Simulation of the Daytime Boundary Layer in an Idealized Valley Using the Weather Research and Forecasting Numerical Model

TitleLarge-Eddy Simulation of the Daytime Boundary Layer in an Idealized Valley Using the Weather Research and Forecasting Numerical Model
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2010
AuthorsCatalano, Franco, and Moeng C.-H.
JournalBoundary-Layer Meteorology
Volume137
Pagination49-75
ISSN00068314
KeywordsAtmospheric movements, Atmospheric thermodynamics, boundary condition, boundary layer, Boundary layer flow, Boundary layers, Budget control, Complex structure, Computational fluid dynamics, Different structure, Electron energy loss spectroscopy, Flow circulation, geostrophic flow, Geostrophic wind forcing, Geostrophic winds, Horizontal breeze, Horizontal resolution, Kinetic energy, Landforms, large eddy simulation, Length scale, Meteorological models, momentum, Momentum flux, Monin-Obukhov similarity theory, Monin-Obukhov theory, numerical model, Numerical models, Orography, Periodic boundary conditions, Periodic ridges, Planetary boundary layers, Soil surface temperatures, Sub-grids, Subgrid scale, Subsidence, Surface flux, Surface flux heterogeneity, Surface measurement, Symmetric geometry, Three dimensional, turbulence, Turbulence kinetic energy, Turbulent kinetic energy, Upslope flows, Vertical direction, Weather forecasting, Weather research and forecasting, wind forcing, Wind power
Abstract

A three-dimensional numerical meteorological model is used to perform large-eddy simulations of the upslope flow circulation over a periodic ridge-valley terrain. The subgrid-scale quantities are modelled using a prognostic turbulence kinetic energy (TKE) scheme, with a grid that has a constant horizontal resolution of 50m and is stretched along the vertical direction. To account for the grid anisotropy, a modified subgrid length scale is used. To allow for the response of the surface fluxes to the valley-flow circulation, the soil surface temperature is imposed and the surface heat and momentum fluxes are computed based on Monin-Obukhov similarity theory. The model is designed with a symmetrical geometry using periodic boundary conditions in both the x and y directions. Two cases are simulated to study the influence of along-valley geostrophic wind forcing with different intensities. The presence of the orography introduces numerous complexities both in the mean properties of the flow and in the turbulent features, even for the idealized symmetric geometry. Classical definitions for the height of the planetary boundary layer (PBL) are revisited and redefined to capture the complex structure of the boundary layer. Analysis of first- and second-moment statistics, along with TKE budget, highlights the different structure of the PBL at different regions of the domain. © 2010 Springer Science+Business Media B.V.

Notes

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URLhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-80755146207&doi=10.1007%2fs10546-010-9518-8&partnerID=40&md5=e9ece9563bb88985461b227574385b78
DOI10.1007/s10546-010-9518-8
Citation KeyCatalano201049