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A diagnosis of Alpine lee cyclogenesis

A diagnosis of Alpine lee cyclogenesis
(1976) ; Alpes ; Cyclogenèse ; Cyclogenèse sous le vent ; Dynamique de l'atmosphère ; Effet orographique ; Europe ; Frontogenèse ; Frontologie ; Géographie physique ; Hiver ; Image satellite ; Lee depression ; Montagne ; Perturbation ; Perturbation
A diagnostic analysis of two cases of lee cyclogenesis in the Alps region is presented (10-12 and 13-15 February 1976). Data used consisted of routinely available rawinsonde, satellite and aircraft data. The study indicates that lee cyclogenesis

Relative dating of moraines based on landform degradation, Lee Vining Canyon, California
California ; Datation ; Datation relative ; Erosion ; Etats-Unis ; Glaciaire ; Géographie physique ; Lee Vining Canyon ; Moraine

Secondary airflow and sediment transport in the lee of a reversing dune
Lee-side windspeed and sediment transport were measured over a small transverse ridge in the Silver Peak dunefield, west-central Nevada, using an intensive array of 25 cup anemometers and 7 total flux traps. From these results, implications
for the mode, direction and relative amount of lee-side sediment transport under crest-transverse flow conditions are discussed.

Britain's imported air pollution

Mountain wave-induced rotors in the lee of the Hex River Mountains
Prefrontal mountain waves frequently occur in the lee of the mountains of the Western Cape in South Africa. On 22 July 2010, four weather balloon soundings were conducted in this area on the upwind and lee sides of the Hex River Mountains
. The purpose of these soundings was to detect rotors that occurred below the trapped lee mountain waves, which can pose a significant danger to general aviation aircraft. The results are analysed and the potential for further investigations suggested. - (AJC)

Secondary flow deflection in the lee of transverse dunes with implications for dune morphodynamics and migration
Measurements of lee-side airflow response from an extensive array of meteorological instruments combined with smoke and flow streamer visualization is used to examine the development and morphodynamic significance of the lee-side separation vortex
over closely spaced transverse dune ridges. A differential deflection mechanism is presented that explains the three-dimensional pattern of lee-side airflow structure for a variety of incident flow angles. The results document the three-dimensional

Numerical simulation of lee cyclogenesis in the Gulf of Genova
Cyclogenèse ; Cyclogenèse sous le vent ; Dynamique de l'atmosphère ; Effet hydrodynamique d'obstacle ; Genova, golfe ; Géographie physique ; Italie ; Lee depression ; Liguria ; Modèle ; Modèle mathématique ; Méditerranée

Dynamics of secondary airflow and sediment transport over and in the lee of transverse dunes
are discussed, including the Law of the Wall; the Jackson and Hunt airflow model; the effects of streamline compression, acceleration and curvature on stoss slope shear stress; and, in particular, recent efforts to characterize secondary lee-side airflow
patterns. A revised conceptual model of lee-side airflow is presented and areas for further research are identified.

Turbulence fields in the lee of two-dimensional transverse dunes simulated in a wind tunnel
The AA. used particle image velocimetry in a wind tunnel simulation to obtain detailed velocity measurements in the lee of two-dimensional transverse dune models, then used the results to analyse their turbulence fields. The dune models used
in this study had a single lee angle of 30°, and a total of 6 stoss angles between 3° and 25°. The AA. used vorticity, turbulence intensity, Reynolds stress and tubulent kinetic energy to characterize the turbulence fields. These parameters were functions
° may have special sigificance in dune development given the characteristics of the mean velocity fields and turbulence fields they produce within the lee airflow. It is the streamwise velocity component and its turbulence that determine the surface

Marginal privatisation and infrastructural deficiencies : Anas and Lee revisited
Les insuffisances en matière d'infrastructures conduisent un certain nombre de branches industrielles à s'écarter du traditionnel monopole public. Anas et Lee ont suggéré six types de comportement de privatisation marginale, susceptibles d'avoir un

Radiation climatology through the trade-wind inversion on the lee slope of Haleakala, Maui, Hawaii

, v-shaped striations and reversed stoss-and-lee clasts are indicative of clasts rotating within this layer. As the till moves it erodes the bedrock and clasts within it. combination of erosion by ice and till produces stoss-and-lee-clasts

This paper presents measurements of sediment deposition on the crest and lee slope of the foredune at Skallingen and combines the results of 2 studies extending over the period 1996 to 2002. These measurements permit examination of the role
of the sand ramps in delivering sediment to the lee slope and lead to the development of a simple conceptual model relating the factors controlling the spatial and temporal development of the ramps.

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