Every year during summer, the wind carries large plumes of desert dust particles from the Sahara Desert in Africa across the Atlantic Ocean.
Now, thanks to satellite data from the European Space Agency (ESA), we can see in incredible detail the extent of this year’s dust plume — it was an unusually large, “Godzilla” plume.
The Saharan dust storm, also known as the Saharan Air Layer, typically forms between late spring and early autumn, peaking in late June to mid-August. Dust particles from the African desert are swept up into the dry air by strong winds and thunderstorms. The dust can then float for days or even weeks on end.
This phenomenon happens every year but the plume now registered is described as unusual due to its size and the distance travelled. Researchers at the National Oceanic and Atmospheric Administration (NOAA) estimated that the dust plume is between 60 to 70% dustier than average, making it the most massive since records began 20 years ago.
The ESA created an animation that shows the spread of particles from the Saharan dust plume moving westward from June 1 to June 26 this year. The data, captured by the ESA’s Copernicus Sentinel and Aeolus satellites, shows the dust plume on its great journey, around 1.8 to 3.7 miles above the ground.
Normally, Saharan dust plumes disperse in the atmosphere and sink into the Atlantic before reaching the Americas, but this wasn’t the case this year, according to satellite data. The dense concentration of dust traveled about 8,000 kilometers and can be seen arriving close to the Caribbean and the southern United States.
The ESA’s Copernicus Sentinel-5P satellite, launched in October 2017, maps air pollutants using an instrument that measures the radiation of different wavelengths. Meanwhile, the Aeolus satellite, launched by the ESA in August 2018, tracks wind speed and direction across the globe.
Aeolus is the first satellite to acquire profiles of Earth’s wind on a global scale the satellite also delivers information about the vertical distribution of aerosol and cloud layers. This combination of data allows scientists to improve their understanding of the Saharan Air Layer, and allows forecasters to provide better air quality predictions.
While it can be a threat to our health, triggering air quality alerts, the dust travelling from the Saharan Desert is also very important for ecosystems. Dust is a key source of nutrients for the tiny algae known as phytoplankton that live drift on the surface of the ocean. Minerals from the dust fall in the ocean, triggering blooms of the algae to form on the surface of the ocean – providing food to marine life.
At the same time, the dust is also very important for life in the Amazon region, replenishing nutrients in the rainforest soils which otherwise would be depleted due to the frequent rain in the region. The dusty air layers have also been found to limit the development of hurricanes and storms in the Pacific.
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Kila mwaka wakati wa majira ya kiangazi, upepo husafirisha vumbi kubwa kutoka Jangwa la Sahara barani Afrika hadi Bahari ya Atlantiki. "Kwa mujibu wa taarifa za satellite kutoka kwa shirika la anga la Ulaya (ESA), ""mchanganyiko wa vumbi wa mwaka huu ni mkubwa sana." Dhoruba ya vumbi ya Sahara, pia inajulikana kama safu ya hewa ya Sahara, kwa kawaida huundwa kati ya mwishoni mwa majira ya kuchipua na mapema vuli, ikifikia kilele mwishoni mwa Juni hadi katikati ya Agosti. Chembe za vumbi kutoka jangwa la Afrika hupeperushwa na upepo mkali na dhoruba za radi kwenye hewa kavu. Kisha vumbi hilo laweza kuelea kwa siku nyingi au hata kwa majuma kadhaa. Jambo hili hutokea kila mwaka lakini wimbi hilo la hewa ambalo limesajiliwa sasa linaelezwa kuwa lisilo la kawaida kwa sababu ya ukubwa wake na umbali uliosafiri. Watafiti wa Shirika la Kitaifa la Usimamizi wa Bahari na Anga (NOAA) wamekadiria kuwa wimbi hilo la vumbi lina kiasi cha asilimia 60 hadi 70 zaidi ya wastani wa wastani wa vumbi duniani, na ni kubwa zaidi tangu kumbukumbu za vumbi hilo zianzishwe miaka 20 iliyopita. ESA imeweka picha ya mlipuko wa vumbi kutoka Sahara kuelekea magharibi kuanzia Juni 1 hadi Juni 26 mwaka huu. Takwimu zilizopigwa na satelaiti za ESA, Copernicus Sentinel na Aeolus, zinaonyesha mlipuko wa vumbi kwenye safari yake kubwa, karibu maili 1.8 hadi 3.7 juu ya ardhi. Kwa kawaida, vumbi la Sahara huenea katika angahewa na kuzama ndani ya Bahari ya Atlantiki kabla ya kufikia Amerika, lakini hii haikuwa kesi mwaka huu, kulingana na data ya satelaiti. Mvua hiyo ilisafiri umbali wa kilomita 8,000 hivi na iliweza kuonekana ikifika karibu na Bahari ya Karibea na kusini mwa Marekani. Satelaiti ya Copernicus Sentinel-5P ya ESA, iliyozinduliwa mnamo Oktoba 2017, inatoa ramani ya uchafuzi wa hewa kwa kutumia kifaa cha kupima mnururisho wa urefu tofauti wa wimbi. Satellite ya Aeolus, iliyozinduliwa na ESA mnamo Agosti 2018, inafuatilia mwendo wa upepo duniani kote. Mfano wa kwanza wa satellite ya Aeolus ni kugundua upepo wa dunia kwa kiwango cha kimataifa na kutoa taarifa kuhusu usambazaji wa aerosol na mawingu. Mchanganyiko huu wa data inaruhusu wanasayansi kuboresha uelewa wao wa Saharan Air Layer, na inaruhusu watabiri kutoa utabiri bora wa ubora wa hewa. Ingawa inaweza kuwa tishio kwa afya yetu, kuamsha tahadhari za ubora wa hewa, vumbi linalosafiri kutoka Jangwa la Sahara pia ni muhimu sana kwa mifumo ya ikolojia. Vumbi ni chanzo muhimu cha virutubisho kwa algae ndogo inayojulikana kama phytoplankton ambayo huishi juu ya uso wa bahari. Madini kutoka vumbi kuanguka katika bahari, triggering blooms ya mwani kuunda juu ya uso wa bahari <unk> kutoa chakula kwa maisha ya baharini. Pia, vumbi ni muhimu sana kwa maisha katika eneo la Amazon, kujaza virutubisho katika udongo wa msitu wa mvua ambayo vinginevyo ingekuwa kupotea kutokana na mvua ya mara kwa mara katika mkoa. Pia imegunduliwa kwamba tabaka za hewa zenye vumbi hupunguza ukuzi wa vimbunga na dhoruba katika Pasifiki. Je, hilo lilisaidia?