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Ann. Geophys., 23, 3187-3193, 2005
www.ann-geophys.net/23/3187/2005/
© European Geosciences Union 2005
Aerodynamic roughness length related to non-aggregated tillage ridges
M. Kardous1, G. Bergametti2, and B. Marticorena2
1Institut des Régions Arides – El Fjé, 4119 Médenine, Tunisie
2Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Universités Paris7–Paris12, CMC, 61 avenue du Général de Gaulle, 94 010 Créteil cedex, France
Abstract. Wind erosion in agricultural soils is dependent, in part, on the aerodynamic
roughness length (z0) produced by tillage ridges. Although previous
studies have related z0 to ridge characteristics (ridge height (RH) and
spacing (RS)), these relationships have not been tested for tillage ridges
observed in the North African agricultural fields. In these regions, due to
climate and soil conditions, small plowing tools are largely used. Most of
these tools produce non-aggregated and closely-spaced small ridges. Thus,
experiments were conducted in a 7-m long wind tunnel to measure z0 for
11 ridge types covering the range of geometric characteristics frequently
observed in south Tunisia. Experimental results suggest that RH2/RS is the
first order parameter controlling z0. A strong relationship between
z0 and RH2/RS is proposed for a wide range of ridge
characteristics.
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