Saharan dust storms, more frequent and more intense, headed to Florida, researchers say

Jim Waymer
Florida Today
NASA researchers are split on whether climate change will result in more or fewer Saharan dust storms.

Orange hazy skies will blanket the Sunshine State by mid week and last through Saturday, forecasters predict.

But new NASA research is split on whether Florida will see more or less of these yearly Saharan dust storms that fuel red tides and many a sneeze.

One new NASA study predicts climate change will drive more frequent and intense dust storms off Africa. Another by the same agency says the opposite.

Dust off the Sahara fertilizes the Atlantic Ocean and American soils. The good news is it can blunt tropical storms, but it also feeds red tide, the Sargassum seaweed that piles up on our beaches every summer and other harmful algae blooms.

Some 60 million tons of the Sahara's nutrient-laden mineral dust lofts into the atmosphere annually, according to NASA, creating a massive layer of hot, dusty air that whisks across the Atlantic with the winds to deliver those nutrients to the ocean and plants in the Caribbean and South America.

The airborne particles block and/or reflect sunlight. In heavy doses near ground, the dust fouls air quality.

In early June, strong winds blew across Mali and Mauritania, carrying the Saharan dust over Senegal, Gambia and Cabo Verde, NASA's Earth Observatory reported in a release. Data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the NASA-NOAA Suomi NPP satellite shows the dust was well out over the central Atlantic Ocean by June 7.

The storm comes a year after NASA documented the largest dust storm in two decades of observations. Saharan dust covered the Caribbean Sea in June 2020, dimming skies over several southeastern states. During that event, satellite and ground sensors measured the highest dust levels in the atmosphere since NASA’s Earth Observing System satellites were launched.

University of Kansas researchers used data from NASA’s Terra and Aqua satellites, Suomi NPP, the joint NASA-CNES CALIPSO satellite, and ground stations to outline how winds carry dust across vast distances.

“The African easterly jet [stream] exports the dust from Africa towards the Atlantic region” said lead author of the study, Bing Pu, said in a NASA release. “Then the North Atlantic subtropical high, which is a high-pressure system sitting over the subtropical North Atlantic, can further transport it towards the Caribbean region. The Caribbean low-level jet, along with the subtropical high, can further transport the dust from the Caribbean region towards the States.”

Read:Three spots to watch in the tropics

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Pu and colleagues hypothesize that climate change will make dust storms more frequent and intense. Higher temperatures will bring more dry air and less vegetation to the Sahara, providing more loose, dusty material to be picked up by winds, they say. Stronger storms and winds in a warmer world also will provide more energy to carry the dust.

A research team led by atmospheric scientist Tianle Yuan of NASA’s Goddard Space Flight Center predicts the opposite.

When the northern Atlantic warms relative to the south Atlantic, trade winds that blow the dust east to west will weaken, the NASA researchers said in the release, transporting less dust from the Sahara. Weaker winds also will enable steadier bands of rain to traverse the tropics and drift north over more of the desert, further dampening dust.

Yuan's team says Africa’s yearly dust plumes might actually shrink over the next 100 years. They argue changes in ocean temperatures will lower prevailing winds and therefore the transport from Africa to the Americas. They also say the wind changes will increase moisture flowing into Africa, leading to more rain and vegetation, reducing dust in the Saharan and Sub-Saharan regions. Global warming could lower Saharan dust by 30% over the next 20 to 50 years, they say, and keep declining after that.

The Sahara Desert is 3.6 million square miles of arid land stretched across the northern half of Africa, slightly smaller than the continental United States.

Read: Three spots to watch in the tropics

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“Dust plays a major role in the Earth system,” said Hongbin Yu, an atmospheric researcher at Goddard. “A decrease of dust as the climate warms may have profound influences on a variety of phenomena, but these potential impacts may be good or bad.” 

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Jim Waymer is environment reporter at FLORIDA TODAY.

Contact Waymer at 321-242-3663                                         

or jwaymer@floridatoday.com.

Twitter: @JWayEnviro

Facebook: www.facebook.com/jim.waymer

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