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Stefano Serafin and Dino Zardi

, slope winds respond to temperature differences between the air heated or cooled by a slope and undisturbed air at the same level ( Prandtl 1952 ; Schumann 1990 ; Haiden 2003 ). At a larger scale, valley winds are generated by thermal imbalances between the core of the valley volume and the atmosphere above a nearby plain. A comprehensive description of the different phases composing the daily cycle of thermally driven flows in a mountain valley, with emphasis on the interaction between slope and

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Stefano Serafin, Lukas Strauss, and Vanda Grubišić

1. Introduction Owens Valley is a narrow valley in eastern California, approximately north–south oriented and bounded by the highest portion of the Sierra Nevada (high sierra) to the west and by the White–Inyo Range to the east. Within such a valley, one expects different types of terrain-induced circulations ( Whiteman 2000 ) to occur. Dynamically driven winds [e.g., topographically channeled flow and intense downslope winds related to mountain waves] are the result of the local modification

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Juerg Schmidli

1. Introduction On fair-weather days, transport and mixing of heat, moisture, and other constituents over mountainous terrain is strongly influenced by the thermally forced mountain circulations, the slope, and valley winds. These mountain flows also play a key role in the formation of clouds and convection initiation ( Banta 1990 ). Also, the quantification of the associated exchange processes is important for many applications such as air-quality studies, numerical weather prediction, and

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Steven K. Sakiyama

OCTOBER 1990 STEVEN K. SAKIYAMA 1015Drainage Flow Characteristics and Inversion Breakup in Two Alberta Mountain Valleys STEVEN K. SAKIYAMAAlberta Department of the Environment, Edmonton, Alberta, Canada(Manuscript received 14 September 1989, in final form 9 April 1990)ABSTRACT Wind and temperature profiles and corresponding acoustic sounder data collected in September 1982 arepresented for

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Lin-Wen Cheng and Cheng-Ku Yu

( Fig. 1b ). The ZZ and HZ ridge arms flank funnel-shaped, lower-terrain regions upstream of the HX valley. Such concave-like mountain ranges are commonly seen in other geographical locations, such as the Cascades in North America, the Alps, and the southeastern Australia, and often have a higher potential to produce severe precipitation ( Frei and Schär 1998 ; Jiang 2006 ; Watson and Lane 2012 , 2014 ). Interactions among orographically modified flows occurring over different portions of the

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Laurence Armi and Georg J. Mayr

1. Introduction A combination of real and virtual topography, as opposed to the real or actual topography alone, will be shown to describe the essentials of stratified flow over mountain ranges and leeside valleys or plains when a layer capped by a strong density step exists above the topography. This cap acts as virtual topography for the stratified flow aloft and will control its response. Vosper (2004) and Jiang (2014) explored the role of such a cap in theoretical and idealized

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Juerg Schmidli and Richard Rotunno

, and climate modeling (e.g., Rotach et al. 2004 , 2008 ; Gohm et al. 2009 ). But they also directly influence the characteristics of local weather and climate such as near-surface temperatures, wind speeds, cloudiness, and precipitation (e.g., Egger et al. 2000 ). Despite the importance of the diurnal mountain winds, there is still some uncertainty regarding the influence of the valley surroundings and the larger-scale plain-to-mountain flow on the dynamics of the valley wind. The major cause

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Juerg Schmidli

1. Introduction The evolution of the diurnal valley winds is the result of complex interactions between solar and thermal radiation, the land surface, turbulence, and the thermally induced flows themselves of various scales, from slope flows to plain-to-mountain circulations (e.g., Whiteman 2000 ; Weigel et al. 2006 ; Schmidli and Rotunno 2010 ). In a recent valley wind model intercomparison study, for example, Schmidli et al. (2011) find large differences in the evolution of the valley

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Eric P. Kelsey, Matthew D. Cann, Kevin M. Lupo, and Liana J. Haddad

contributing to the CAP and mountain flow exiting the HBEF valley into the Pemigewasset River valley. The air in the upper part of the CAP likely originated from the reservoir of free atmospheric air above the CAP that has little temperature change at night. Free tropospheric and/or residual layer air continually feeds into the katabatic flow on the upper slopes because of continuity, is cooled along the slopes, and then flows across the upper part of the CAP. The bottom of the CAP likely maintained a

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Morgan F. Chrust, C. David Whiteman, and Sebastian W. Hoch

nocturnal down-valley flows inside the canyon ( thermally driven exit jets ). Thermally driven exit jets, the focus of this paper, occur most readily under the relatively quiescent large-scale weather conditions that produce diurnal mountain circulations. Despite anecdotal descriptions of the regular occurrence of these flows in many mountain regions, relatively little scientific attention has been focused on thermally driven canyon exit jets (hereinafter referred to simply as canyon or valley-exit jets

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