Ripple Effect

Just as a pebble tossed into a calm pond causes ripples of water that radiate for some distance, tiny particles thrown up into the atmosphere--like this dust from a Saharan dust storm--can cause climatic ripples thousands of miles away.

Aerosols are known to have a cooling effect on the planet's surface because they absorb and therefore block incoming solar radiation so that it can't reach the ground to heat it up.

But after these particles absorb the incoming solar radiation, they radiate it away as heat and warm surrounding atmosphere.

Researchers had thought this heating would only cause local temperatures changes, but a new computer model created by William Lau at the NASA Goddard Space Flight Center showed that the heat generated by the aerosols creates large waves that, like those caused by the pebble, ripple through the atmosphere to places as far away as the North Pacific.

Lau ran simulations of the atmosphere over the Sahara Desert in the springtime when weather conditions were calm, allowing the dust to build up high in the atmosphere. Storms can carry the dust thousands of miles away, where it can affect the local weather--a phenomenon called a teleconnection; in the model simulation, these teleconnections caused cooling over the Caspian Sea and warming over central and northeastern Asia.

--LiveScience Staff

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Credit: NOAA