Wind profile constants in a neutral atmospheric boundary layer over complex terrain

Kustas, William P.; Brutsaert, Wilfried

doi:10.1007/bf00120907

Cited by 64 publications

(47 citation statements)

References 25 publications

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“…Th is is considerably higher than the value of 10% which is often taken as the thickness of the surface layer of a turbulent boundary layer. This is a confirmation of the earlier findings of Kustas and Brutsaert (1986) in the rugged terrain of the Swiss Fore-Alps. Evidently the rule-of-thumb of 10% is only applicable to surfaces with smaller roughness.…”

Section: Concluding Summarysupporting

confidence: 91%

“…As a further illustration of the neutrality of profile, it should be possible to determine these parameters from the profile observations. However, rawinsonde data are usually quite noisy as a result not only of turbulence (i.e., short-term sampling) but also of instrumental error (see also Kustas and Brutsaert, 1986). Therefore it is desirable to reduce the number of unknown parameters to the absolute minimum and to constrain the equation to ensure proper behavior.…”

Section: Description Of Experimentsmentioning

confidence: 99%

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Regional roughness of the landes forest and surface shear stress under neutral conditions

Parlange

Brutsaert

1989

Boundary-Layer Meteorol

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Abstract. Mean wind velocity profiles were measured by means of radio-windsondes over the Landes region in southwestern France, which consists primarily of pine forests with scattered villages and clearings with various crops. Analysis of neutral profiles indicated the existence of a logarithmic layer between approximately .z -4 = 67(*18)z, and 128(*32)z, (z is the height above the ground, z0 the surface roughness and do the displacement height). The upper limit can also be given as z -do = 0.33 (kO.l8)h, where h is the height of the bottom of the inversion. The profiles showed that the surface roughness of this terrain is around 1.2 m and the displacement height 6.0 m. Shear stresses derived from the profiles were in good agreement with those obtained just above the forest canopy at a nearby location with the eddy correlation method by a team from the Institute of Hydrology (Wallingford, England).

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Section: Concluding Summarysupporting

confidence: 91%

Section: Description Of Experimentsmentioning

confidence: 99%

Regional roughness of the landes forest and surface shear stress under neutral conditions

Parlange

Brutsaert

1989

Boundary-Layer Meteorol

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“…Observations (Grant and Mason, 1990;Kustas and Brutsaert, 1986) have shown that small hills tend to produce a logarithmic wind profile above themselves, typical of a large roughness length. Therefore, roughness length In the latter case, a drag force is applied in the Nature and Town tiles for the wind.…”

Section: Orographic Frictionmentioning

confidence: 99%

The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

et al. 2013

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Abstract. SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs) or in coupled mode (from mesoscale models to numerical weather prediction and climate models). An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy). Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

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“…Wood and Mason, 1993) and field (e.g. Kustas and Brutsaert, 1986;Grant and Mason 1990) studies have supported the hypothesis that the equivalent homogeneous surface approach using effective parameters is valid for representing non-homogeneous surfaces. In fact, the effective parameter approach is inevitable to describe evaporation over an area in many cases, since the actual surface is almost always heterogeneous and it is impossible to describe every roughness obstacle on the surface in the equation to estimate evaporation.…”

Section: Introductionmentioning

confidence: 81%

Effect of roughness distribution on evaporation processes over non‐homogeneous sand surfaces: a wind tunnel investigation

Sugita

Kishii

2002

Hydrological Processes

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Abstract:A series of wind tunnel experiments were conducted to investigate the effect of surface roughness distribution on evaporation processes. In particular, the relationship between non-homogeneous roughness distribution parameters and effective roughness parameters, which are often required to estimate the evaporation rate over a heterogeneous area, were examined closely. A number of sand ridges having various distributions were placed perpendicular to the main wind direction on a 3 m long lysimeter (1 m in width and 0Ð6 m in depth) filled with fine sand. The groundwater table in the lysimeter was maintained at a constant level ranging from 0Ð1 to 0Ð55 m below the surface. The lysimeter was fitted to the wind tunnel, in which incoming airflow was controlled to have a constant velocity, temperature, and humidity. An internal boundary layer was formed on the sand surface and the mean profiles of wind velocity, humidity, and temperature were observed within this layer. In total, 99 profiles over 33 different surfaces were obtained. The roughness parameters for each surface were evaluated by fitting the mean profile equations to the observed profiles. The following effects of roughness distribution on evaporation and the effective roughness parameters were found.(1) An increase in standard deviation of the roughness distribution, which is the variation in obstacle intervals, caused an increase in the evaporation rate when the average roughness spacing was constant and relatively large. (2) The interrelationships among effective roughness z m , z v , and z h can be described by the same function that describes that of homogeneous surfaces. (3) Evaporation from rough surfaces was more sensitive to the depth of groundwater than that from the smooth surface within our experimental conditions, because the rough surfaces allow soil water over a broader range of depth to reach the surface. The first two results suggest that the effective roughness parameters are a function of the average and perturbation of roughness distribution on the surface and that the effective z v and z h values can be estimated from effective z m value.

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Wind profile constants in a neutral atmospheric boundary layer over complex terrain

Cited by 64 publications

References 25 publications

Regional roughness of the landes forest and surface shear stress under neutral conditions

Regional roughness of the landes forest and surface shear stress under neutral conditions

The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

Effect of roughness distribution on evaporation processes over non‐homogeneous sand surfaces: a wind tunnel investigation

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