HR: 14:40h
AN: NG43A-05    [Abstracts]
TI: Sediment Transport and Dust Flux in Disturbed and Undisturbed Dryland Ecosystems: From Site Specific Estimates to Trends Across Gradients of Woody Plant Cover
AU: * Field, J P
EM: jpfield@email.arizona.edu
AF: School of Natural Resources, University of Arizona, PO Box 210043, Tucson, AZ 85721- 0043, United States
AU: Breshears, D D
EM: daveb@email.arizona.edu
AF: School of Natural Resources, University of Arizona, PO Box 210043, Tucson, AZ 85721- 0043, United States
AU: Breshears, D D
EM: daveb@email.arizona.edu
AF: Institute for the Study of Planet Earth, University of Arizona, PO Box 210156, Tucson, AZ 85721-0043, United States
AU: Breshears, D D
EM: daveb@email.arizona.edu
AF: Department of Ecology and Evolutionary Biology, University of Arizona, P.O. Box 210088, Tucson, AZ 85721-0043, United States
AU: Whicker, J J
EM: jjwhicker@lanl.gov
AF: Health Physics Measurements Group, Los Alamos National Laboratory, Mail Stop G761, Los Alamos, NM 87545, United States
AU: Zou, C B
EM: czou@email.arizona.edu
AF: School of Natural Resources, University of Arizona, PO Box 210043, Tucson, AZ 85721- 0043, United States
AU: Allen, C D
EM: craig_allen@usgs.gov
AF: USGS Jemez Mountains Research Center, HCR 1, Box 1, #15, Los Alamos, NM 87544, United States
AB: Aeolian sediment transport and associated dust flux are important processes in dryland ecosystems where vegetation cover is inherently sparse relative to more mesic ecosystems. Aeolian processes in dryland ecosystems are strongly influenced by the spatial density of roughness elements, which is largely determined by woody plant height and spacing. Despite the global extent of dryland ecosystems, relatively few measurements of aeolian sediment transport have been made within these systems, and these few existing measurements have not been systematically evaluated with respect to gradients of woody plant cover. We report measured aeolian sediment transport in an undisturbed and disturbed semiarid grasslands in southern Arizona. To place our estimate in a broader context, we compared our site-specific findings to other recently published measurements of aeolian sediment transport in disturbed and undisturbed dryland ecosystems. We propose a new conceptual framework for dryland aeolian sediment transport and dust flux as a function of woody plant cover that integrates our site-specific data with the broader literature base. Our findings suggest that for relatively undisturbed ecosystems, shrublands have inherently greater aeolian sediment transport and associated dust flux than grasslands, woodlands and forests due to wake interference flow associated with the height and spacing of woody roughness elements. Furthermore, the proposed framework suggests that for disturbed ecosystems, the upper bound for aeolian sediment transport increases as a function of decreasing woody plant cover. As a result, aeolian sediment transport spans a relatively small range in woodlands and forests, an intermediate range in shrublands, and the largest range in grasslands. Our framework is applicable both within locations and across broad gradients
DE: 1622 Earth system modeling (1225)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1824 Geomorphology: general (1625)
DE: 4430 Complex systems
DE: 4490 Turbulence (3379, 4568, 7863)
SC: Nonlinear Geophysics [NG]
MN: 2007 Fall Meeting