|Gillette, D. - NOAA|
|Herbert, G. - G.A. HERBERT ASSOC|
Submitted to: Journal of Fluid Mechanics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 19, 2005
Publication Date: June 1, 2006
Citation: Gillette, D.A., Herrick, J.E., Herbert, G.A. 2006. Wind characteristics of mesquite streets in the Northern Chihuahuan Desert, New Mexico, USA. Environmental Fluid Mechanics. 6:241-275. Interpretive Summary: The most active sand movement in the mesquite-dominated ecosystems has been shown to take place on elongated bare soil patches between shrubs. These areas are often referred to as “streets”. This study was designed to improve our understanding of how this unique vegetation pattern results in a highly variable mosaic of soil erosion through its effects on wind speed and direction near the soil surface. The results can be used to help predict wind erosion in areas that shrub-dominated ecosystems.
Technical Abstract: Past research has shown that the most important areas for active sand movement in the northern part of the Chihuahuan Desert are mesquite-dominated desert ecosystems possessing sandy soil texture. The most active sand movement in the mesquite-dominated ecosystems has been shown to take place on elongated bare soil patches referred to as “streets”. Aerodynamic properties of mesquite streets eroded by wind should be included in explaining how mesquite streets are more emissive sand sources than surrounding desert land. To understand the effects of wind properties, we measured them at two 'at mesquite sites having highly similar soil textures but very different con'gurations of mesquite. The differences in wind properties at the two sites were caused by differences of size, orientation, and porosity of the mesquite, along with the presence of mesquite coppice dunes (sand dunes stabilized by mesquites growing in the dune and on its surface) found only at one of the two sites. Wind direction, u' (friction velocity), z0 (aerodynamic roughness height) and D (zero plane displacement height) were estimated for 15-m tower and 3-m mast data. These aerodynamic data allowed us to distinguish 've categories with differing potentials for sediment transport. Sediment transport for the 've categories varied from unrestricted, free transport to virtually no transport caused by vegetation protection from wind forces. In addition, “steering” of winds below the level of the tops of mesquite bushes and coppice dunes allowed longer parallel wind durations and increased wind erosion for streets that aligned roughly SW–NE.