Scientists in the United Arab Emirates have discovered that the largest dust storm ever recorded in Africa may have been triggered by jet streams farther north. The study was published recently in Geophysical Research Letters.
In late June, the dust storm godzilla moved toward northwest Africa at speeds of more than 70 kilometers per hour. The dust storm affected an area nearly the size of the continental United States, carrying 24 million tons of material and a volume equivalent to thousands of Olympic-sized swimming pools. The cause of the jet is unclear, but researchers have linked Godzilla to a warming Arctic and melting sea ice, Science reported.
The scale and form of Godzilla is staggering, and the effects are profound: phosphorus can reach the roots of trees in the Amazon rainforest, and tiny dust particles can pollute the air across the Caribbean.
Normally, sandstorms form when monsoons on the southern edge of the Sahara blow moist air to the ground.
But godzilla’s trigger was linked to a large area of high-pressure air stuck over the northwestern edge of Africa — triggering four days of strong northeasterly winds that lifted dust up to 6km into the air, and a westerly African jet stream that created a dust storm.
The researchers also found that the high-pressure system appeared at the same time as the polar jet at the North Pole and dropped to a much lower latitude than usual. These atmospheric waveforms form a series of high and low pressure weather systems that encircles the northern Hemisphere for several weeks during the summer. At the same time, a high-pressure system was also forming in Siberia.
Corresponding author Diana Francis is from Khalifa University of Science and Technology.
She said that while the cause of jet streams and weather systems is unclear, studies have suggested that arctic warming due to melting sea ice may be the culprit. The Arctic is warming faster than other regions, and the narrowing of the temperature difference between north and mid-latitudes could make the jet more unstable.
But some researchers have reservations about the idea. They argue that it is hard to find a strong direct link between a chaotic and complex weather system and arctic warming.