The position of the jet (blue shading) during the Palm Sunday tornado outbreak from 1965.

A study from the Carnegie Institution has shown that the jet streams in both hemispheres have risen in altitude and have shifted slightly toward the poles over the 23-year period between 1979 and 2001. The shift in the jet streams could be due to global warming and fits the prediction of global warming models, according to the report.

The researchers used data that included outputs of weather prediction models, conventional observations from weather balloon and surface intrumentation along with remote observations from satellites.

Some of the specific findings from the study........

--The jet stream in the northern hemisphere has been shifting north at a rate of 12 miles per decade, which I agree is very small, but also pretty meaningless. The authors note that if the trend continues then it could cause some problems.....but when?

--The northern hemisphere jet has also weakened.

--As the jet stream moves toward the poles, tropical cyclones could become more frequent and stronger, since the influence of stronger winds aloft typically inhibit tropical development and create shear.

One of the lead researchers of the project, Ken Caldeira, personally thinks this change in the jet streams is a result of global warming, but he cannot say for sure. He is very confident (he is willing to bet $$$$ folks!) that this trend (shift in jet streams) will continue.

On a sad note............

Edward Lorenz, an MIT professor and meteorologist who developed the chaos theory, died Wednesday at the age of 90. The Boston Globe wrote a nice piece yesterday on Dr. Lorenz and here is an exerpt from the obituary that some may want to consider when they proclaim that the tiny increase in atmospheric CO2 cannot possibly cause a major change the future behavior of the global climate system.........

From the Globe,

His work on the theory began a decade earlier. In the winter of 1961, Dr. Lorenz was trying to determine how accurate a computer could predict long-term weather patterns. He ran one simulation with a computer model, then wanted to extend the forecast, so he added a second simulation, with the same parameters and conditions of the first model. The weather pattern should have seamlessly flowed into the second simulation.

Instead, the trajectories quickly diverged.

The problem: a rounded decimal number. Dr. Lorenz realized that the computer stored numbers to an accuracy of six decimal places but, to save space, printed out results shortened to three decimal places. So, for example, 0.310625 became 0.311. For the second simulation, he had used the shortened figure.

Even this minute discrepancy drastically altered the forecast.

Tiny changes, in effect, could have catastrophic, and often unpredictable, consequences. And they made perfect predictions of weather, even through the emerging power of computers, impossible: Exact measurements of all the conditions could be upset by one small event, such as the flap of a gossamer wing.

Very interesting stuff! The professor and his work will be deeply missed.