HR: 1340h
AN: A33B-0899    [Abstracts]
TI: Calibration of a New Type of Wind Tunnel (PI-SWERL) With Dust Emission Data From a Conventional Straight-Line Wind Tunnel
AU: * Sweeney, M
EM: mark.sweeney@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512-1095 United States
AU: Etyemezian, V
EM: vic.etyemezian@dri.edu
AF: Desert Research Institute, 755 E. Flamingo Rd, Las Vegas, NV 89119-7363 United States
AU: Gillies, J
EM: jack.gillies@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512-1095 United States
AU: MacPherson, T
EM: tmacpher@uoguelph.ca
AF: Department of Geography, University of Guelph, Guelph, Ont 91G2W1 Canada
AU: McDonald, E
EM: eric.mcdonald@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512-1095 United States
AU: Nikolich, G
EM: nicolic@dri.edu
AF: Desert Research Institute, 755 E. Flamingo Rd, Las Vegas, NV 89119-7363 United States
AU: Nickling, W
EM: nickling@uoguelph.ca
AF: Department of Geography, University of Guelph, Guelph, Ont 91G2W1 Canada
AB: The Portable In Situ Wind ERosion Lab (PI-SWERL) was developed by the Desert Research Institute to measure dust emissions from soil surfaces. This small, portable unit can test the emissivity of soils in areas that are difficult to access with a straight field wind tunnel, and can complete a larger number of tests in less time. The PI-SWERL, embodied in a cylindrical enclosure (0.6 m diameter, 0.3 m height), contains an annular flat blade that is controlled to rotate at varying speed, which generates a shear stress upon the surface. Laboratory measurements using skin friction meters (Irwin sensors) were used to estimate the relation between rotation speed and shear stress imparted onto the test surface. The shear stress generated by PI-SWERL results in the entrainment of particles on the surface that dislodge dust, the concentration of which is measured using real-time instrumentation (TSI Model 8520 DustTrak). The straight portable wind tunnel is currently the best instrument available to characterize dust emission fluxes from soils in lieu of measurements taken during actual wind erosion events. PI-SWERL does not simulate the atmospheric boundary layer in the same manner as the field wind tunnel, but was developed to provide a comparable index of dust emission potential. This paper will present results of the calibration of PI-SWERL with the 11 m long by 1 m wide University of Guelph portable field wind tunnel that was conducted at 15 relatively flat, non-vegetated sites at the Ft. Irwin National Training Center, CA and the Mojave National Preserve. A wide spectrum of soils with different propensities to emit dust was tested including sand- to clay-rich soils on eolian, lacustrine (playa), and alluvial landforms. Soil surfaces displayed a range of crusting, some with gravel cover, and were either undisturbed or artificially disturbed for testing. At each site, seven to ten wind tunnel tests were conducted and ten to eighteen PI-SWERL tests were run adjacent to the wind tunnel test locations. For any given soil type, an empirical correspondence is expected between PI-SWERL and wind tunnel measurements because the processes of dust emissions in both cases are driven largely by shear stress at the surface. The development and calibration of the PI-SWERL as an accepted technique to measure dust emissions will result in easier and faster measurements, and complement current research efforts that tie soil and landform type to dust emission potential.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0394 Instruments and techniques
DE: 0486 Soils/pedology (1865)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005