Simulations of spatial variability in particle-size emissions during wind erosion events

Butler, Harry J. and McTainsh, Grant H. and Hogarth, William L. (2012) Simulations of spatial variability in particle-size emissions during wind erosion events. Earth Surface Processes and Landforms, 37 (13). pp. 1362-1375. ISSN 0197-9337

Abstract

This study simulates how spatial variations in particle-size emissions from a playa affect bulk and size-resolved dust concentration profiles during two contrasting wind erosion events (a small local and a large regional event) in the Channel Country, Lake Eyre Basin, Australia. The regional event had higher dust concentration as a result of stronger frontal winds and higher erodibility across the playa. For each event, two emission scenarios are simulated to determine if measured size-resolved dust concentration profiles can be explained by spatial variability in source area emissions. The first scenario assumes that particle-size emissions from source areas occur at a uniform rate, while the second scenario assumes that particle-size emissions vary between and within source areas. The uniform emission scenario, reproduced measured bulk dust concentration profiles (R2 = 093 regional and R2 = 081 local), however simulated size-resolved dust concentration profiles had poor statistical fits to measured size-resolved profiles for each size class (the highest were R2 = 05 regional and R2 = 03 local). For the differential particle-size emission scenario, the fit to the measured bulk dust concentration profiles is improved (R2 = 097 regional and R2 = 083 local). However, the fit to the size-resolved profiles improved dramatically, with the lowest being R2 = 089 (regional) and R2 = 080 (local). Particle-size emission models should therefore be tested against both bulk and size-resolved dust concentration profiles, since if only bulk dust concentration profiles are used model performance may be over-stated. As the source areas in the first 90 m upwind of the tower were similar for both events, the percentage contributions of each particle-size class to total emissions can be compared. The contribution of each particle-size class was similar even though the wind speed, turbulence and dust concentrations were significantly different; suggesting that the contribution of each particle-size to the total emitted dusts is not related to wind speed and turbulence.


Statistics for USQ ePrint 21593
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published online 25 June 2012. Permanent restricted access to ArticleFirst version.
Depositing User: Dr Harry Butler
Faculty / Department / School: Historic - Faculty of Sciences - Department of Maths and Computing
Date Deposited: 12 Sep 2012 11:58
Last Modified: 03 Jul 2013 01:15
Uncontrolled Keywords: wind erosion; dust plume; dust sources; dust particle-size
Fields of Research (FOR2008): 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040607 Surface Processes
05 Environmental Sciences > 0503 Soil Sciences > 050302 Land Capability and Soil Degradation
04 Earth Sciences > 0401 Atmospheric Sciences > 040101 Atmospheric Aerosols
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9601 Air Quality > 960199 Air Quality not elsewhere classified
D Environment > 96 Environment > 9602 Atmosphere and Weather > 960201 Atmospheric Composition (incl. Greenhouse Gas Inventory)
Identification Number or DOI: doi: 10.1002/esp.3245
URI: http://eprints.usq.edu.au/id/eprint/21593

Actions (login required)

View Item Archive Repository Staff Only