Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The apparent roughness of a sand surface blown by wind from an
  analytical model of saltation   We present an analytical model of aeolian sand transport. The model
quantifies the momentum transfer from the wind to the transported sand by
providing expressions for the thickness of the saltation layer and the apparent
surface roughness. These expressions are derived from basic physical principles
and a small number of assumptions. The model further predicts the sand
transport rate (mass flux) and the impact threshold (the smallest value of the
wind shear velocity at which saltation can be sustained). We show that, in
contrast to previous studies, the present model's predictions are in very good
agreement with a range of experiments, as well as with numerical simulations of
aeolian saltation. Because of its physical basis, we anticipate that our model
will find application in studies of aeolian sand transport on both Earth and
Mars.

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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
1
The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
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The categories of this paper are: alg-geom