Changing jet streams may alter storm paths

STANFORD, Calif., April 17 (UPI) -- U.S. scientists say changes in the Earth's jet streams, possibly caused by global warming, might affect storm paths and intensity, including hurricanes.

Jet streams -- high-altitude bands of fast-moving winds -- are shifting, said Carnegie Institution researchers Ken Caldeira and Cristina Archer. They found that from 1979 to 2001, the jet streams in both hemispheres rose in altitude and shifted toward the poles. At the same time, northern hemisphere jet streams weakened.

Since jet streams are the driving factor for weather conditions, said Archer, changes in the jets have the potential to affect large populations and major climate systems.

Caldeira and Archer, from Carnegie's Department of Global Ecology in Stanford, Calif., said hurricanes' development tends to be inhibited by jet streams. Therefore hurricanes might become more powerful and more frequent as the jet streams move away from sub-tropical zones where hurricanes are born.

The scientists said the changes fit the predictions of several global warming models, although theirs is the first study to use observation-based datasets to examine trends in all the jet stream parameters.

The research appears in the journal Geophysical Research Letters.