On the efficiency of vertical array aeolian field traps

Authors

  • KELD R. RASMUSSEN,

    1. 1 Department of Earth Sciences, University of Aarhus, DK 8000 A−1pt−3.5ptrhus C, Denmark (E-mail: geolkrr@aau.dk), 2Department of Agrometeorology, Danish Institute of Plant and Soil Science, Research Centre Foulum, PO Box 23, DK-8830 Tjele, Denmark (E-mail: HM@afa.sp.dk)
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  • HARALD E. MIKKELSEN

    1. 1 Department of Earth Sciences, University of Aarhus, DK 8000 A−1pt−3.5ptrhus C, Denmark (E-mail: geolkrr@aau.dk), 2Department of Agrometeorology, Danish Institute of Plant and Soil Science, Research Centre Foulum, PO Box 23, DK-8830 Tjele, Denmark (E-mail: HM@afa.sp.dk)
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Abstract

The efficiency of three vertical array field traps for measuring the distribution of aeolian mass transport with height was compared with measurements with an isokinetic trap. The vertical traps seem to work adequately (efficiency > 80%) at heights greater than ≈15 mm above the bed. Closer to the bed, however, the open array trap catches about 70%, the two continuous arrays only about 50%. Because most of the transport takes place close to the surface, the overall efficiency of the field traps ranges from 50 to 70%.

Based on these wind tunnel tests, we have developed a low single-compartment wedge-shaped trap. Its shape, in combination with flow straighteners at the entrance, minimizes stagnation effects, so that the efficiency is ≈80%. Our data indicate that with the wedge trap used in combination with the vertical array Aberdeen trap, we can sample mass transport in the field during periods with unidirectional winds with an overall efficiency of the order of 80%.

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