Tuesday, April 2, 2013

Saharan Sand: A Hindrance & Initiation of Weather


There is an invisible element out there that has the power to erode mountaintops, change landscapes, and in some cases carry sand and dust particles thousands of kilometers across the world’s atmosphere. I speak of wind. Wind is a powerful and mysterious element that exists even on the most distant planets. We can only bear witness to its effects since air is invisible to the naked eye. However sometimes, such as in the featured image, we can witness wind in disguise. Notice that in the picture, there is a faint band that stretches across the sea. That band is actually airborne sand particles and dust particles from the Sahara Desert, being carried thousands of kilometers across the barren Atlantic. The sand becomes kicked up into the atmosphere and affects global weather patterns in many ways.

Recent research from NASA suggests that these dust particles, once settled on the ocean water’s surface, block out some of the sunlight which in turn cools the water. In 2006, there were significantly more dust storms in the Sahara which scientists think may explain the generally quiet 2006 hurricane season. More dust storms would yield more airborne particles which in turn would settle on and cool the ocean surface. Since hurricanes thrive off of warm water, the cooler water would hinder the development of strong and more frequent hurricanes. However, some scientists debate on whether or not the Saharan dust is enough to influence such large storms and claim that the quiet 2006 hurricane season was due more to the effects of El NiƱo.

Nevertheless, airborne dust and sand that originated from the Sahara do in fact affect the planet’s weather. In addition to travelling west over the Atlantic, airborne dust is also known to travel east, out of the Sahara and eventually all the way across the Pacific Ocean where it ends its journey in California in the form of precipitation. In this case, the dust becomes airborne and somewhat trapped in the atmosphere where it acts as nuclei within clouds. The particles initiate the crystallization of ice and then once the cloud has reached its saturation point, the frozen particles are released as rain, snow, or hail.

So next time you witness a snowstorm, consider that at the center of each snowflake there may or may not be a tiny sand or dust particle that traveled from the Sahara, thousands of miles through the atmosphere and across the Pacific, just to land on your sleeve; a primal example of how our planet is interconnected even on the tiniest of levels.


Photo Credit:
Andre Kuipers / ESA / NASA

References:
1. http://www.nasa.gov/mission_pages/hurricanes/archives/2007/hurricane_dust.html
2. http://scrippsnews.ucsd.edu/Releases/?releaseID=1327
3. https://www.scientificamerican.com/article.cfm?id=asian-and-african-dust-influences-north-american-weather
4. http://science.time.com/2013/01/22/a-room-with-a-view-scenes-from-the-international-space-station/photo/6832380432_461a2a58cf_b/


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