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Aeolian mass transport near the saltation threshold
Author(s) -
Rasmussen Keld R.,
Sørensen Michael
Publication year - 1999
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/(sici)1096-9837(199905)24:5<413::aid-esp997>3.0.co;2-i
Subject(s) - aeolian processes , mass transport , mechanics , sediment transport , wind speed , geology , shear stress , mass flux , shear velocity , environmental science , atmospheric sciences , meteorology , soil science , geotechnical engineering , hydrology (agriculture) , geomorphology , physics , turbulence , engineering physics , sediment
Aeolian mass transport was investigated in a desert field experiment where the wind speeds were near the saltation threshold. Bed transport was observed during 45 min runs even though the calculated values of bed shear stress using conventional laboratory equations for mass transport predicted that there should be no transport. We therefore investigated the possibility of predicting mass transport using quasi‐instantaneous wind speeds, i.e. values derived at a time scale similar to that of the saltation process. Quasi‐instantaneous wind speeds are able to predict mass transport associated with the stronger gusts. Predicted mass transport values compare fairly well with observation, but the accuracy of the prediction is very sensitive to correct estimation of the surface roughness and the saltation threshold for the particular sand bed. When these values differ by only 10 percent from the values that optimize the estimation, predicted mass transport can differ by up to ±50 per cent. Copyright © 1999 John Wiley & Sons, Ltd.