Saharan dust and its journey around the world
Discover how weather conditions can whip up sand from the Sahara Desert and carry it around the world
Saharan dust is a mixture of dust and sand from the Sahara Desert. When very strong winds pass over the desert, this mixture blows up into the sky to form clouds, which can reach astonishingly high altitudes. Winds in the upper part of the atmosphere then transport these dust clouds, also known as the Saharan Air Layer, towards the UK. The particles are capable of traveling thousands of kilometres on these dust-laden winds, crossing land and entire oceans where they even become visible on other continents. But you need something to wash it out of the sky. As rain falls from the atmosphere it collects the dust particles on the way down. When the raindrops land on a surface they evaporate, leaving behind a layer of dust. Not only does this dust layer result in hazy skies, but sometimes it also causes shorter-wavelength ‘blue’ light to be scattered away, leaving behind longer wavelength ‘red’ light to shine through. This gives the appearance of orange-red skies.
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