Wind Tunnel Experiments of Aeolian Dust Deposition Along Ranges of Hills

Abstract

Wind tunnel experiments of aeolian dust deposition on topographic scale models of ranges of hills were conducted. Different hill sizes and hill spacings were used, and comparisons with the deposition patterns over single, isolated hills were made. Dust profiles over ranges of hills differ from the profiles over identical, but isolated hills. On isolated hills the sedimentation maximum on the windward hillslope is always single and located on the concave part of the slope. In the case of ranges of hills, the maximum is either single or double, with the second peak on the convex part of the windward slope in the latter case. The local sedimentation maximum on the convex leeslope, which is rather unimportant on isolated hills, is much more developed in multiple-hill topography. Also, dust deposition on the leeslopes is significantly higher in multiplehill topography than on isolated hills.Dust patterns on ranges of hills may be affected by the dust shadow created by the most upstream-located hill. If hills succeed each other quickly, they are located within the shadow zone and are protected from important dust deposition.The plume of high air dust concentration that is created by a hill largely determines the dust pattern on the next hill. As a result of the supply of dust from above by the descending plume, areas that are normally devoid of dust now experience significant dust deposition.

Preferential Deposition of Snow and Dust Over Hills: Governing Processes and Relevant Scales

“…The particle mass flux reflects some of the features of the flow field. As experimentally observed by Goossens (), the horizontal particle supply to the valleys is almost negligible (Figure b) as most of the mass flux is provided vertically by the flow downdrafts (Figure c).…”

“…We validate our model against wind tunnel measurements of dust deposition onto isolated hills (Goossens, ) and sequential hills (Goossens, ). These experimental studies provide us with detailed information on flow field, sediment, and deposition patterns and are thus ideal test cases for the validation of our model.…”

Using 137Cs to estimate wind erosion and dust deposition on grassland in Inner Mongolia-selection of a reference site and description of the temporal variability

“…The selection of an appropriate reference site in a wind erosion/dust deposition area was based on fluid dynamical principles as shown in previous wind tunnel and field studies by Goossens (1988Goossens ( , 1996Goossens ( , 2006. Summit positions have the lowest dust depositions because of the local increase of the wind speed.…”

“…On the other hand higher wind speed promotes wind erosion, so the site should also be characterized by a dense vegetation or litter cover to prevent soil losses. In complex terrain a downwind hill is influenced by a dust-shadow effect by an upwind hill and almost free of dust deposition (Goossens 1996), so this aspect should also be considered, if possible. Last but not least the site should be plane or only slightly sloped to exclude additional influences of water erosion.…”

Spatial associations between infestations of mountain pine beetle and landscape features in the Peace River Region of British Columbia.

“…those with bodies greater than a 4 or 5 mm 2 surface area, like mountain pine beetle) are less likely to be carried over top of a barrier to enter circulating leeward eddies because of their great inertia (Lewis and Dibley 1970). Hills that are relatively close to each other will also increase the amount of deposition on the windward slope of consecutive hills (Goossens 1996). The topography in the western portion of the Peace River region is characterized by consecutive ridges and valleys, causing ridgelines downwind to sustain more insect deposition on windward, southwestern slopes.…”