Wednesday, July 15, 2009

Is African drought related to La Niña?

Maybe.

Here's the deal. La Niña is basically over, but its effects might be teleconnected to other parts of the planet. Africa has been hit with drought. Is it La Niña related? Well, both the drought locations and precipitation distribution seem to fit the pattern.

Drought in Africa

El Niño and La Niña: Impacts and Predictions

One example of ENSO’s global climate impact is its link to December-February rainfall in Mozambique and south east Africa. During La Niña periods, south east Africa experiences a higher likelihood of excess rainfall, and floods. And this is exactly what happened in this region from 1998-2001.

Compare this predicted pattern (you can click it to see it on a white background):













to the precipitation (top) and drought (bottom) patterns for June. These are from the Earth Observatory article linked above. In the top image, blue is higher-than-normal precip, brown is lower than normal. Southeast Africa is wet, just like in the prediction. In the bottom image, brown is abnormally dry vegetation, green is greener-than-normal. Note the intense brownness to the east of Lake Victoria and the Rift Valley lakes, just about the same as the prediction.

Astute readers, if there are any, will note that the images below are for June and the predictions are for December-January. Well, La Niña conditions weren't really gone until April. So I submit there's some persistence here.






















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