The sand of the Sahara, with an event of exceptional scope, has reached in recent days even the Caribbean islands covering about 6-7 thousand kilometers from the African hinterland and flying over the skies of the Atlantic Ocean. It is the “largest Saharan dust cloud of the past 50 years” as defined by the European Defense Industry and Space.
#GodzillaDustCloud
An ad hoc hastag, literally “Godzilla cloud of dust”, was also created to identify the extraordinary extension of the sandy dust which took 4 days, from 13 to 17 June, to fly over the ocean waters and invade the skies of some Caribbean islands where it even caused real sand storms. The suspended sand, however, was renewed in the Caribbean skies until June 26 because it was continuously fed by currents that, from east to west, have not stopped transporting the dust as seen in the simulation attached below.
#GodzillaDustCloud, the largest Saharan dust cloud in 50 years covered the Atlantic Ocean over more than 7000 km
See its evolution with the data acquired between 13-26 June by the @CopernicusEU #Sentinel5P @Tropomi sensor#SaharanAirLayer #Dust #SaharanDust
FYI @NLSpaceOffice pic.twitter.com/81kNFiOFzs– DG DEFIS #UnitedAgainstCoronavirus (@defis_eu) June 29, 2020
“Historical event”
The World Meteorological Organization (Wmo) spoke about the event historical which involved a large spatial extension of the large Caribbean area, from the south-eastern Caribbean just off the north coast of South America even going as far as the Yucatan peninsula in Mexico. “African sand flies over the Atlantic skies every year but this year’s event has been particularly intense and extensive,” reads the Wmo website. “This is a dusty event of truly historic proportions“the meteorologists added.
The more islands affected were Martinique, Guadeloupe and Puerto Rico where the Saharan dust has reached very high concentrations with pm10 levels that have exceeded the threshold of 500 mg per cubic meter, extremely dangerous for air quality and breathing. These are record concentrations that have not been recorded for at least twenty years and, to find comparable concentrations, it is necessary to go back even 50 years.
How sandstorms originate
Sand and dust storms are common weather hazards in arid and semi-arid regions. Usually they are caused from storms or strong pressure gradients associated with cyclones that increase wind speed over a large area. These strong winds lift large quantities of sand and dust into the atmosphere from bare, dry soils, transporting them hundreds or thousands of kilometers away. Every year about 2 thousand million enter the atmosphere tons of dust: much of this is a natural process, but it is also the result of poor management of water resources and the territory.
Natural fertilizer for soils
This phenomenon is called “Saharian Air Layer”, the fine grains of sand remain suspended in the atmosphere, are transported by low-level winds and reach a thickness of between three thousand and four thousand meters, as stated in Meteolive. It is a phenomenon that contributes to fertilization Soil: this is why soils affected by frequent episodes of this type, as happens very often also in Italy and in the Mediterranean countries, are particularly suitable for cultivation facilitating agriculture.
Research has shown that iron-rich particles found in these sandstorms reflect sunlight, cooling in this way the atmosphere. The particles also reduce the amount of sunlight that reaches the ocean which in turn reduces the warming of the surface of the seas as the sand cloud passes.
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