Easterbrook, Don J. Department of Geology, Western Washington University, Bellingham, Washington.
Last reviewed:November 2019
- Movement of particles by wind
- Eolian abrasion and erosion
- Sand dunes
- Related Primary Literature
- Additional Reading
Topographic features formed mainly by wind in regions with much loose sand, silt, or clay. An estimated 500 million metric tons (556 million tons) of dust per year are transported by the wind. Airflow in wind can be either laminar or turbulent, but is mostly turbulent. Wind blowing across the land surface contains many swirls and eddies, some of which produce upward components of movement. Generally, the higher the mean wind velocity, the greater the amount of upward turbulence. The ratio of the velocity of upward turbulent gusts near the ground to mean wind velocity varies, but it averages about 1:5. Thus, particles whose settling velocities are lower than one-fifth of the mean wind velocity are likely to be conveyed upward by wind gusts and transported downwind. Larger particles remain mostly close to the ground until unusually high gusts lift them up. Small eddies occur under most atmospheric conditions, unless the air is unusually thermally stable. As wind velocity rises, corkscrew eddies develop with axes parallel to the mean wind direction; and larger, horizontal eddies, measured in hundreds of meters, are superimposed on the smaller, corkscrew eddies. See also: Clay; Dust storm; Laminar flow; Sand; Velocity; Wind
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 10,000 highly qualified scientists and 45 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information