Impact of wind on the spatial distribution of rain over micro‐scale topography: numerical modelling and experimental verification

Blocken, Bje Bert; Poesen, Jean; Carmeliet, JE Jan

doi:10.1002/hyp.5865

Cited by 47 publications

(31 citation statements)

References 50 publications

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“…The uniformity coefficients of the rainfall intensity changed from 82% for the rains driven by wind speed of 12.0 ms − 1 with the nozzle pressure of 75 kPa to 92% for those driven by 6.4 ms − 1 with the nozzle pressure of 150 kPa (Erpul, 1996). The actual amount of rain intercepted on a sloping surface with respect to the prevailing wind direction was calculated with the angle of rain incidence using the correction factors (Sharon, 1970(Sharon, , 1980Sharon et al, 1983Sharon et al, , 1988De Lima, 1990;Sharon and Arazi, 1997;Blocken and Carmeliet, 2000, 2002, 2004Blocken et al, 2005;Cornelis et al, 2004a;Blocken et al, 2006):…”

Section: Methodsmentioning

confidence: 99%

Sand detachment under rains with varying angle of incidence

Erpul

Gabriëls

Cornelis

et al. 2008

CATENA

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In the case of wind-driven rain, as the angle of rain incidence increases, greater force components act parallel to the surface and lower force components act perpendicular to the surface. Therefore, raindrop impact angle could influence the detachment process in the existence of substantial lateral jet development. This could be particularly significant for a cohesionless sand surface that has a weaker resistance to the dislodgement by a raindrop impact than a soil surface. Experiments of simulated wind-driven rain were conducted to evaluate sand detachment rates under increased lateral jetting induced by wind velocities of 6.4, 10.0, and 12.0 m s − 1 at nozzle operating pressures of 75, 100, and 150 kPa and incident on windward and leeward slopes of 4 and 9°. With these set-ups, it was possible to have varying angles of incidence and to determine the effect of the compressive stress and shear stress, evaluated by the horizontal and vertical kinetic energy fluxes (E tx and E tz , respectively), on the detachment rates from the sand surface. At the same vectorwise sum of E tz and E tx , the results showed that there was, for similar values of E tz and E tx in windward slopes, more sand detachment rate; however, for dissimilar values of E tz and E tx in leeward slopes where E tx was significantly higher than E tz , there was less sand detachment rate. Consequently, with certain values of the compressive stress and shear stress, the sand detachment rates under wind-driven rains peaked; and E tz was the limiting component since the rates significantly decreased as E tz particularly decreased in spite of very large values of E tx .

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Section: Methodsmentioning

confidence: 99%

Sand detachment under rains with varying angle of incidence

Erpul

Gabriëls

Cornelis

et al. 2008

CATENA

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“…Two major reasons are that some aspects are more exposed to rain and wind, especially in periods with intense rainfall, and the terrain is unusually steep (> 20°). The geometrical equation of Fourcade (1942) and Blocken et al (2006):…”

Section: 2mentioning

confidence: 99%

Slope aspect affects geomorphic dynamics of coal mining spoil heaps in Belgium

Nyssen

Vermeersch

2010

Geomorphology

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After the abandonment of coal mining in Belgium in the 1960s-1980s, many coal tips have been left to themselves. Increasingly, these coal tips are regarded as socio-cultural heritage and protected for their environmental value. This research analyses the spatial distribution of the main geomorphic processes (sheet and rill erosion, landsliding, rock fragment movement and root throw) occurring on coal tips in Belgium, through mapping of the processes and their causal factors. Five spoil heaps spread over the major coal basins were studied in detail. The spoil heaps were subdivided in homogeneous land units, especially with regard to slope gradient, vegetation cover and slope aspect. Qualitative and quantitative observations were done on processes and potential causal factors. Regressions showed that generally, the expression of slope processes on the studied coal tips is (1) strongly dependent on westerly aspect of the slopes, (2) independent of slope gradient (which presents a narrow range), (3) impeded by grass cover, and (4) not fully predictable due to variability in type and age of dumped mine spoil.

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“…The amount of rill erosion strongly depends on the amount of hydrological rainfall, the rainfall as it would be measured by a tilted rain gauge with its orifice parallel to the soil surface, per unit of horizontally projected orifice area (Blocken et al, 2006). The meteorological rainfall is the amount of rainfall as measured by a conventional rain gauge with a horizontal orifice, per unit orifice area (Blocken et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…The meteorological rainfall is the amount of rainfall as measured by a conventional rain gauge with a horizontal orifice, per unit orifice area (Blocken et al, 2006). The amount of hydrological rainfall depends on various factors: geometry of the ground surface, location in the topography, wind velocity, slope aspect, rain intensity and the size of the raindrops (Blocken et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Impact of slope aspect on hydrological rainfall and on the magnitude of rill erosion in Belgium and northern France

BEULLENS

Velde

Nyssen

2014

CATENA

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The impact of slope aspect on hydrological rainfall and on the magnitude of rill erosion has rarely been studied. The dominant wind direction in Belgium and the northern of France is the southwest, which brings large amounts of rain with it. We investigated whether this leads to greater rates of rill erosion on the southwestern slopes, due to the greater amount of hydrological precipitation on these slopes. The study was executed on six barren conical spoil heaps, which are excellent study objects to bring the slope aspect in relation with rill erosion.Three indicators for rill erosion (volume of rills, drainage density and mean distance of the head cut of the five uppermost rills till the top of the spoil heap) were associated with four explanatory factors (slope gradient, vegetation density, rock fragment cover and slope aspect).The amount of hydrological rainfall is the greatest on the western and southwestern slopes. As a result, the largest volume of rills was measured on the slopes facing the southwest (96%), which indicates that there is a connection between the slope aspect and the magnitude of rill erosion. On the northeastern (32%) and eastern (36%) slopes the volume of rills is lower due to the effect of rain shadow. The other explanatory factors showed little influence on the magnitude of rill erosion, as the spoil heaps were selected to be similar in as many parameters as possible.Beullens, J., Van de Velde, D., Nyssen, J., 2014. Impact of slope aspect on hydrological rainfall and on the magnitude of rill erosion in Belgium and northern France. Catena,

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Impact of wind on the spatial distribution of rain over micro‐scale topography: numerical modelling and experimental verification

Cited by 47 publications

References 50 publications

Sand detachment under rains with varying angle of incidence

Sand detachment under rains with varying angle of incidence

Slope aspect affects geomorphic dynamics of coal mining spoil heaps in Belgium

Impact of slope aspect on hydrological rainfall and on the magnitude of rill erosion in Belgium and northern France

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