Teleconnections: Long-distance Relationships

 

Predicting the flooding of a specific river several months in advance might never be possible, but a global, long-term archive of flood events could reveal possible teleconnections between flooding events in different locations. Teleconnections are climate anomalies that are related but often widely spaced in distance and/or time.

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  Map of El Nino's teleconnections
 

The relationship between the two climate patterns is not necessarily cause and effect. Often both out-of-the-ordinary climate phenomena are caused by some third factor, such as when El Niño events increase the chance of above-average precipitation in the U.S. Southwest from January through March and increase the chance of drought in Indonesia from June through August.

Brakenridge said that a few teleconnections between flooding events seem to be emerging from the archive, but that they need more time and data to establish a solid correlation. “We also see somewhat predictable locations of where floods occur during El Niño years,” he added. If the search for teleconnections is successful, the relationships could one day be used to make regional predictions of seasonal flooding several months in advance.

 

The El Niño/Southern Oscillation is the most prominent of Earth’s teleconnections. The eastern Pacific (left of image center) and the western Pacific (right of center) are connected over thousands of miles by an inverse relationship in which the central and western Pacific off South America get much more rain than normal during El Niño events, while the eastern Pacific between Southeast Asia and Australia often suffers drought. The reverse pattern occurs during La Niña years. (Image courtesy JPL TRMM Team)