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J. R. Garratt

in this experimental data scatter. Future experiments must provide detailed measurements of theseparameters and of the wave structure, with carefulconsideration given to instrumental performance, ifsuch effects are to be resolved. Over land, vertical momentum transfer over largeareas can probably be evaluated realistically usingeffective drag coefficients or roughness parameters.These must account for both the frictional drag (dueto vegetation, etc.) and form drag introduced by perturbation of

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Steven E. Koch, Wayne Feltz, Frédéric Fabry, Mariusz Pagowski, Bart Geerts, Kristopher M. Bedka, David O. Miller, and James W. Wilson

and 60-m height resolution over a depth of ∼2.5–4.0 km ( Cohn et al. 2001 ). MAPR was the only system that provided direct and frequent measurements of winds. Five-minute dropouts occurred on the half-hour because of Radio Acoustic Sounding System (RASS) sampling. Two National Aeronautics and Space Administration (NASA) lidars were used in this study: the Scanning Raman Lidar (SRL; Whiteman et al. 2006a , b ) and the Holographic Airborne Rotating Lidar Experiment (HARLIE; Schwemmer et al. 1998

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Edward I. Tollerud, Fernando Caracena, Steven E. Koch, Brian D. Jamison, R. Michael Hardesty, Brandi J. McCarty, Christoph Kiemle, Randall S. Collander, Diana L. Bartels, Steven Albers, Brent Shaw, Daniel L. Birkenheuer, and W. Alan Brewer

simultaneous lidar measurements of moisture and wind. We next focus attention on the bulk properties and effects of scales of motion in section 4 by computing layer-averaged fluxes through sections that bracket the LLJ. From these results, we are able to compute Reynolds averages within the layers, from which we estimate the bulk effect of so-called “prime–prime” terms, interpreted as integrated estimates of the contribution of small-scale (mesoscale to convective scale) circulations to the overall

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James D. Doyle, Qingfang Jiang, Ronald B. Smith, and Vanda Grubišić

flow response is governed by ĥ and the mountain Rossby number, Ro = U / fL , where f is the Coriolis parameter and L is the mountain half-width (e.g., Gill 1982 ; Pierrehumbert and Wyman 1985 ; Thorsteinsson 1988 ). For large Ro (>10), rotational effects are weak and the response is primarily governed by vertically propagating gravity waves ( Gill 1982 ). Inertia–gravity waves dominate when Ro ∼ 1, which are characterized by quasi-horizontal energy propagation and relatively small

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Tobias Selz and George C. Craig

dependent on the structure and amplitude of the initial perturbation ( Zhu and Thorpe 2006 ). In contrast, the errors on convective scales grow at the location of the convection ( Zhang et al. 2007 ) and seem to be almost insensitive to the perturbation method ( Hohenegger and Schär 2007b ) (i.e., their amplitude and spatial structure). Even small-amplitude acoustic waves are sufficient to generate significant divergence of two simulations on the convective scale after about 10 h. Larger sensitivity to

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