Fine dust emissions from active sands at coastal Oceano Dunes, California
<p>Sand dunes and other active sands generally have a low content of fine grains and, therefore, are not considered to be major dust sources in current climate models. However, recent remote sensing studies have indicated that a surprisingly large fraction of dust storms are generated from reg...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/2947/2019/acp-19-2947-2019.pdf |
| Summary: | <p>Sand dunes and other active sands generally have a low content of fine grains
and, therefore, are not considered to be major dust sources in current
climate models. However, recent remote sensing studies have indicated that a
surprisingly large fraction of dust storms are generated from regions covered
by sand dunes, leading these studies to propose that sand dunes might be
globally relevant sources of dust. To help understand dust emissions from
sand dunes and other active sands, we present in situ field measurements of
dust emission under natural saltation from a coastal sand sheet at Oceano
Dunes in California. We find that saltation drives dust emissions from this
setting that are on the low end of the range in emissions produced by
non-sandy soils for similar wind speed. Laboratory analyses of sand samples
suggest that these emissions are produced by aeolian abrasion of feldspars
and removal of clay-mineral coatings on sand grain surfaces. We further find
that this emitted dust is substantially finer than dust emitted from
non-sandy soils, which could enhance its downwind impacts on human health,
the hydrological cycle, and climate.</p> |
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| ISSN: | 1680-7316 1680-7324 |