The "double jet-stream", a phenomenon that could be linked to heat waves

A fourth heat wave has affected France since Monday.

This heat wave, which will last until the end of the week, may not be the last of the summer.

As reported by

, a study published last July 4 in

by researchers at the Potsdam Research Institute for the Effects of Climate Change (PIK) indeed shows that much of eastern Europe West is currently stuck in a current of hot air favored by a “double jet-stream” effect.

Disturbed functioning

Originally, the jet-stream is a corridor of powerful winds which in particular makes it possible to regulate in Europe the currents of cold air coming from Greenland and the currents of hot air coming from the Sahara.

But, with global warming, the initial functioning of the jet stream seems to have been disrupted.

The masses of cold air in Greenland, the region that is warming the most in the world, have indeed weakened.

Its current of air is therefore more and more insufficient to counter that of the Sahara.

As a result, the jet stream migrated north and even slowed down.

A heat trap

In return, this slowing down causes more and more frequently a split in two of the current of the jet-stream: the double jet-stream.

This division completely changes the way it works.

Instead of repelling the hot air from the Sahara, it now encloses it between its two branches.

Thus, according to the researchers, 30% of the intensity of heat waves in Europe between 1979 and 2020 is linked to this effect.

This percentage even rises to 100% for Western Europe.

The 2003 heat wave is mainly explained by this phenomenon.

Increased monitoring of the jet stream could thus make it possible to better anticipate future heat waves.

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