@inbook {50443, title = {Eolian processes across the Jornada basin}, booktitle = {Structure and Function of a Chihuahuan Desert Ecosystem. The Jornada Basin Long-Term Ecological Research Site}, year = {2006}, month = {July 1, 2006}, pages = {189-210}, publisher = {Oxford University Press}, organization = {Oxford University Press}, chapter = {9}, address = {New York}, abstract = {In arid and semiarid lands, soil erosion by wind is an important process that affects both the surface features and the biological potential of the ecosystem. The eolian flux of soil nutrients into or out of an ecosystem results in enrichment or impoverishment of its biological potential. In the Jornada Basin, wind erosion is the only significant mechanism for the net loss of soil materials because fluvial processes do not remove materials from the basin. Vigorous wind erosion leads to topographic changes, altering the growing conditions for plants and animals. Examples of such changes in topography are the formation of sand dunes or the removal of whole soil horizons. Our goal in this chapter is to describe the construction of a mathematical model for wind erosion and dust production for the Jornada Basin. The model attempts to answer the following questions:1. Which soils are affected by wind erosion?2. How does wind erosion occur on Jornada soils?3. Does changing vegetation cover lead to a change in the source/sink relationship? 4. Is the Jornada a source or sink of eolian materials? If it is a source, what materials are lost?5. How does wind erosion change the soil-forming process?}, keywords = {biological, ecosystem, eolian, erosion, soil, wind}, url = {/files/bibliography/06-060.pdf}, author = {D. E. Gillette and Curtis H. Monger}, editor = {Kris Havstad and L. Huenneke and W. H. Schlesinger} } @article {50444, title = {Wind characteristics of mesquite streets in the northern Chihuahuan desert, New Mexico, USA}, journal = {Environmental Fluid Mechanics}, volume = {6}, year = {2006}, month = {June 1, 2006}, pages = {241-275}, 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 {\textquotedblleft}streets{\textquotedblright}. 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 {\textquoteright}at mesquite sites having highly similar soil textures but very different con{\textquoteright}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{\textquoteright} (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 {\textquoteright}ve categories with differing potentials for sediment transport. Sediment transport for the {\textquoteright}ve categories varied from unrestricted, free transport to virtually no transport caused by vegetation protection from wind forces. In addition, {\textquotedblleft}steering{\textquotedblright} 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{\textendash}NE. http://www.springerlink.com/content/y572665mn2j7n828/fulltext.pdf

}, keywords = {Chihuahuan Desert, desert vegetation, desert winds, dunes, dust emissions, flow around and above roughness elements, friction velocity, sand transport, vegetation}, doi = {10.1007/s10652-005-6022-7}, url = {/files/bibliography/06-026.pdf}, author = {D. E. Gillette and Jeffrey E. Herrick and Herbert, G.A.} } @article {50655, title = {A combined modeling and measurement technique for estimating wind-blown dust emissions at Owens (dry) Lake, CA}, journal = {Journal of Geophysical Research}, volume = {109}, year = {2004}, note = {//NONE//NONE// Listed in LTER IV 2004 annual report}, month = {2004}, pages = {1-23}, abstract = {

The problem of dust emissions from playa sources is an important one both in terms of human health and in terms of global dust issues, distribution of loess, and mineral cycling. A refined method of modeling atmospheric dust concentrations due to wind erosion was developed using real-time saltation flux measurements and ambient dust monitoring data at Owens Lake, California. This modeling method may have practical applications for modeling the atmospheric effects of wind erosion in other areas. Windblown dust from the Owens Lake bed often causes violations of federal air quality standards for particulate matter (PM10) that are the highest levels measured in the United States. The goal of this study was to locate dust source areas on the exposed lake bed, estimate their PM10 emissions, and use air pollution modeling techniques to determine which areas caused or contributed to air quality violations. Previous research indicates that the vertical flux of PM10 (Fa) is generally proportional to the total horizontal saltation flux (q) for a given soil texture and surface condition. For this study, hourly PM10 emissions were estimated using Fa = K' {\texttimes} m15, where m15 is the measured sand flux at 15 cm above the surface, and K' was derived empirically by comparing air quality model predictions to monitored PM10 concentrations. Hourly sand flux was measured at 135 sites (1 km spacing) on the lake bed, and PM10 was monitored at six off-lake sites for a 30 month period. K' was found to change spatially and temporally over the sampling period. These changes appeared to be linked to different soil textures and to seasonal surface changes. K' values compared favorably with other Fa/q values measured at Owens Lake using portable wind tunnel and micrometeorological methods. Hourly trends for the model-predicted PM10 concentrations agreed well with monitored PM10 concentrations. Dust production was estimated at 7.2 {\texttimes} 104 t of PM10 for a 12 month period. A single storm accounted for 9\% of the annual dust emissions at 6.5 {\texttimes} 103 t. The modeling results were used to identify 77 km2 of dust-producing areas on the lake bed that will be controlled to attain the federal air quality standard for PM10.

}, keywords = {aeolian processes, dust emissions, aeolian processes, Owen Lake, article, articles, journal, journals, model, dust emission, wind transport, Owens Lake}, isbn = {F01003, doi:10.1029/2003JF000025}, doi = {10.1029/2003JF000025}, url = {files/bibliography/JRN00403.pdf}, author = {D. E. Gillette and Ono, D. and Richmond, K.} } @article {50656, title = {Sand flux in the northern Chihuahuan desert, New Mexico, USA, and the influence of mesquite-dominated landscapes}, journal = {Journal of Geophysical Research}, volume = {109}, number = {F04003, doi:10.J029/2003JF000031}, year = {2004}, month = {2004}, abstract = {

Measurements of sand flux over areas with different vegetation in the Chihuahuan desert show that mean, height-integrated, horizontal flux values for mesquite-dominated sites were higher than those for other kinds of vegetation. Sand transport over mesquite areas displayed seasonal variability for most years. This seasonal variability roughly followed the variability of strong winds. Sand transport rates for collectors within a short distance downwind of mesquite bushes were small compared to those for collectors at the end of streets (elongated patches of bare soil) aligned with wind direction. The increased rate of sand transport (wind erosion) associated with mesquite is important because mesquite-dominated areas are increasing in the northern Chihuahuan desert and are therefore responsible for increasing land degradation (desertification).

}, keywords = {Chihuahuan Desert, desert vegetation, dust emissions, journal article, mesquite, sand flux, sand transport}, doi = {10.1029/2003JF000031}, url = {/files/bibliography/04-010.pdf}, author = {D. E. Gillette and Pitchford, A.M.} } @article {50657, title = {A {\textquoteleft}{\textquoteleft}test of concept{\textquoteright}{\textquoteright} comparison of aerodynamic and mechanical resuspension mechanisms for particles deposited on field rye grass (Secale cercele). Part 1. Relative particle flux rates}, journal = {Atmospheric Environment}, volume = {38}, year = {2004}, note = {//NONE//NONE// Listed in LTER IV 2004 annual report//Added 08/10/2004, Updated 05/16/2006}, month = {2004}, pages = {4789-4797}, abstract = {Resuspension of uniform latex micro spheres deposited on a single seed pod of field rye grass stalk and head was investigated experimentally in a wind tunnel. The experiment was designed to distinguish aerodynamic (viscous and turbulent) mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 10 mm. Wind tunnel tests were run for wind speeds from 2 to 18.5ms1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1. Our experiments showed the following for our test of concept experiment:* Resuspension particle flux increases when mechanical impacts occur.* Mechanical resuspension dominated for 2 mm particles over purely aerodynamic resuspension, but for larger particles aerodynamic mechanisms were roughly equally effective in resuspending particles.}, keywords = {aeolian processes, transport, aerodynamic, aerosol, article, grass, journal, resuspension, wind tunnel}, author = {D. E. Gillette and Robert E. Lawson Jr. and Roger S. Thompson} } @article {50658, title = {A {\textquoteleft}{\textquoteleft}test of concept{\textquoteright}{\textquoteright} comparison of aerodynamic and mechanical resuspension mechanisms for particles deposited on field rye grass (Secale cercele). Part 2. Threshold mechanical energies for resuspension particle fluxes}, journal = {Atmospheric Environment}, volume = {38}, year = {2004}, note = {//NONE//NONE// Listed in LTER IV 2004 annual report//Added 08/10/2004, Updated 05/16/2006}, month = {2004}, pages = {4799-4803}, abstract = {Kinetic energy from the oscillatory impacts of the grass stalk against a stationary object was measured with a kinetic energy measuring device. These energy inputs were measured as part of a resuspension experiment of uniform latex microspheres deposited on a single rye grass seed pod in a wind tunnel. The experiment was designed to measure resuspension from aerodynamic (viscous and turbulent) mechanisms compared to that from mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 8.1 {\`\i}m. Wind tunnel tests were run for wind speeds from 2 to 18.5ms-1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1.Our experiments showed the following:* Threshold mechanical energy input rates increased from 0.04 to 0.2 mJs-1 for resuspension of spherical polystyrenelatex particles from 2 to 8.1 {\`\i}m diameter.* Kinetic energy flux generated by mechanical impact of the wind-driven oscillating grass was found to be highlysensitive to slightly different placements and grass morphology.* The kinetic energy input by impaction of the grass against a stationary cylinder is roughly proportional to the kineticenergy flux of the wind.}, keywords = {aeolian processes, transport, aerodynamic, aerosol, article, grass, journal, resuspension, wind tunnel}, author = {D. E. Gillette and Robert E. Lawson Jr. and Roger S. Thompson} } @proceedings {50868, title = {The long-distance A {\textquoteleft}transportable fraction{\textquoteright} of the vertical flux of wind-transported dust}, volume = {Publication 02-2}, year = {2002}, note = {//??//LTER IV// Listed in LTER IV annual reportProCite field[6]: In}, month = {2002}, abstract = {A "lumped control volume" approach is used here to gain understanding of fugitive dust sources including wind erosion and road dust emission. This case considers dust generated from a road surface. A semiempirical model expresses in a simple expression the "transportable fraction" of dust generated at ground level and carried by the wind.}, keywords = {abstract, abstracts, aeolian processes, wind-transported dust, conference, conference proceedings, conferences, proceeding, proceedings, wind transport}, author = {D. E. Gillette}, editor = {Lee, Jeffrey A. and Teddy M. Zobeck} } @article {50989, title = {Particle production and aeolian transport from a "supply-limited" source area in the Chihuahuan desert, New Mexico, United States}, journal = {Journal of Geophysical Research}, volume = {106}, number = {D6}, year = {2001}, note = {//USDA//LTER IV//entered 07/16/2001;correction 08/19/2008}, month = {2001}, pages = {5267-5278}, abstract = {Wind erosion mechanisms were investigated for the "scrape site" at the Jornada Experimental Range near Las Cruces, New Mexico, in the Chihuahuan desert. The scrape site was denuded of vegetation and scraped flat in 1991. We adopted the site in 1994 because it offered an opportunity to study wind erosion mechanisms for a large area of unprotected sandy and crusted soil in an otherwise natural setting and over a period of several years. We installed and operated the following instrumentation for a period of 35 months; three meteorological towers, each 2 m in height, with wind speed sensors at 0.2, 0.5, 1.0, and 2.0 m above ground; air temperature at 0.2 and 2 m height; rain gauge; seven sets of particle collectors at 0.1, 0.5, and 1.0 m heights; and three fast-response particle mass flux sensors at 0.02, 0.1, 0.2, and 0.5 m heights; all along a transect crossing the site and parallel to the predominant southwesterly wind direction. The minimum threshold friction velocity for the scrape site with a thin layer of loose material was 25 cm s-1. This minimum threshold velocity increased to as high as 100 cm s-1 depending on the degree of particle depletion and the site{\textquoteright}s status which varied between supply unlimited just after a high wind episode and supply limited which was more typical for the rest of the time. The dominant mechanism producing fresh sediment for transport was sandblasting of the surface crust. The measurements showed that supply and availability of loose, fine particles on the surface is a strong control of rates of erosion rather than wind energy alone.}, keywords = {aeolian processes, particle production, aeolian processes, Scrape Site, aeolian processes, transport, article, articles, dust emission, journal, journals, soil erosion, wind erosion}, author = {D. E. Gillette and Chen, Weinan} } @article {50990, title = {Supply-limited horizontal sand drift at an ephemerally crusted, unvegetated saline playa}, journal = {Journal of Geophysical Research}, volume = {106}, number = {D16}, year = {2001}, note = {//NONE//LTER IV//entered 07/29/2005; updated 07/28/2008, 07/30/2008}, month = {2001}, pages = {18085-18098}, abstract = {

A site at Owens Dry Lake was observed for more than 4 years. The site was a vegetation-free saline playa where the surface formed {\textquotedblleft}ephemeral crusts,{\textquotedblright} crusts that form after rainfall. Sometimes these crusts were destroyed and often a layer of particles on the crust would engage in vigorous aeolian activity. Three {\textquotedblleft}phases{\textquotedblright} of active sand drifting are defined as almost no movement (extreme supply limitation), loose particles on crust with some degree of sand drift (moderate supply limitation), and unlimited source movement corresponding to a destroyed surface crust (unlimited supply). These {\textquotedblleft}phases{\textquotedblright} occurred 45, 49, and 6\% of the time, respectively. The accumulation of loose particles on the crust was mostly the result of in situ formation. Crusted sediments with loose particles on top can exhibit mass flux rates about the same as for noncrusted sediments. Crusted sediments limit or eliminate sand drift in two conditions: for rough crusts that effect a sufficiently high threshold friction velocity (above the wind friction velocity) and for limited amounts of loose particles on the crust where particle supply is less than would be transported in normal saltation for a thick sandy surface. These {\textquotedblleft}supply-limited{\textquotedblright} cases are similar to wind erosion of limited spilled material on a hard concrete surface. We quantified {\textquotedblleft}supply limitation{\textquotedblright} by defining a {\textquotedblleft}potential{\textquotedblright} or {\textquotedblleft}supply unlimited{\textquotedblright} sand drift function Q = AG where A represents supply limitation that decreases as the particle source is depleted. Here Q is the mass of sand transported through a surface perpendicular to the ground and to the wind and having unit width during time period t, and G = ∫ u*(u2* - u2*t) dt for u* \> u*t. G is integrated for the same time period t as for Q, u* is the friction velocity of the wind, and u*t is the threshold friction velocity of the wind. Hard crusts (usually formed in the summer) tended to show almost no change of threshold friction velocity with time and often gave total protection from wind erosion. Rough crusts provided sufficient protection expressed as high threshold friction velocities. For these high threshold friction velocities, aeolian activity was greatly reduced or practically prevented. The softest crusts, usually formed in the winter, provided much less protection and sometimes were destroyed by the wind. Following this destruction the {\textquotedblleft}potential{\textquotedblright} or {\textquotedblleft}supply unlimited{\textquotedblright} sand drift would be observed.

}, keywords = {aeolian processes, Owen Lake, aeolian processes, particle production, aeolian processes, roughness elements, aeolian processes, transport, aeolian processes, wind erosion, aeolian processes, wind-transported dust, article, journal, Owens Dry Lake}, doi = {10.1029/2000JD900324}, url = {files/bibliography/JRN00346.pdf}, author = {D. E. Gillette and T. Niemeyer and Paula Helm} } @article {51147, title = {A qualitative geophysical explanation for "hot spot" dust emitting source regions}, journal = {Contributions to Atmospheric Physics}, year = {1999}, note = {//??//LTER III// Record added 01/25/2000}, month = {1999}, keywords = {article, articles, dust sources, eolian processes, journal, journals}, author = {D. E. Gillette} }