# Airborne Horizontal Mass Flux Calculated With Different Equations

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Paper number  052049,  2005 ASAE Annual Meeting . (doi: 10.13031/2013.18903) @2005
Authors:   Daniel E. Buschiazzo, Ted M. Zobeck
Keywords:   Wind Erosion, Saltation, Airborne Dust, Horizontal Mass Flux

The quantification of airborne material passing by a vertical plane as a function of height, the horizontal mass flux (HMF), is essential in measuring field wind erosion. Two commonly used equations to calculate HMF are : Q = a Z-b [1], where Q is the amount of dust collected, Z the height, and a and b are regression coefficients: and Q = fo(1 + (Z/ ) [2] where fo = is the movement of the soil at the soil surface, and are regression coefficients. Since the integration of the eroded material as a function of height can be performed from 0 (surface) with equation [2] but not with equation [1], an evaluation of these equations is needed because different HMF estimates often occur among equations. Calculations were made for 28 storms using dust samplers placed at heights of a) 13.5, 50 and 150 cm (Q3) and b) 0.15, 0.7, 1.5, 7, 12, 22.5, 13.5, 50 and 150 cm (Q9). HMF calculated with equations [1] and [2] correlated well but HMF of equation [1] were 40 to 55% lower than those of equation [2]. The averaged fitting of the amount of transported material with height was lower and more variable when using equation [1] than when using equation [2]. These results showed that HFM obtained with equation [1] are highly dependent on sampling height, and need to be corrected on the basis of data obtained closer to the surface before they can be used to test wind erosion prediction models, unlike HMF obtained using equation [2].