BACK END
GEOLOGY INDEX
STUDY QUESTIONS
Fewer than 10% of the world's deserts are covered by dunes. Sand dunes vary in size depending on the sand supply and wind direction. Some of the more common types include: 
Name of dune
Appearance
Sand Supply Wind strength Vegetation
Transverse . abundant moderate absent
Longitudinal . moderate high absent
Star (seif) . limited variable absent
Barchan limited moderate absent
Parabolic . abundant moderate some
In Florida, the main areas affected by the wind are near beaches. Worldwide though, it is well to keep in mind that even in deserts, most erosion is done by running water in patterns similar to those discussed under the section on streams.