African Dust: How Do Its Emission and Transport Alter the Climate?

African dust, also known as the Saharan Dust Layer, is a dust cloud that forms every year due to the storms in the Saheel region. The winds send plumes of dust across the Atlantic to the Americas.

Scientists have long studied how dust scattered across the planet by winds could alter the climate. Emission and transport of African dust can sometimes reach the poles, although they fluctuate considerably.

A recently published paper, titled "The discovery of African dust transport to the western hemisphere and the Saharan air layer: A history" in the Bulletin of the American Meteorological Society, chronicles its history.

The team of researchers led by the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science Professor Emeritus Joseph M. Prospero included African dust's discovery in the Caribbean Basin in the 1950s and 1970s, its emission, and transport.

History of African Dust Transport

Winds lift the mineral-rich African dust from the Sahara Desert and carry it on a 5,000-mile journey across the North Atlantic to the Americas. the dust contains iron, phosphorus, and other essential minerals that support life in marine and terrestrial ecosystems, such as the Amazon Basin. The African dust also plays a significant role in altering the climate by modulating solar radiation and cloud properties.

According to the university's news release, the paper also discusses the discovery of African dust and its link between dust transport ad climate following an increase in dust transport to the Caribbean because of the drought in the Sahel region. Today, studies on African dust are focused on North Africa as it is the planet's largest and most persistent source of dust.

Professor Prospero, dubbed as the "father of dust," used a system of ground stations and satellites to study the effect of dust emissions from the Sahara Desert to the atmospheric composition above the Caribbean.

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African Dust Can Alter the Climate

The Sahara Desert emits dust that mostly ends up in oceans. The Saharan dust emissions affect climate, block or reflect the sunlight, and affect the formation of clouds and hurricanes. The dust is made up of 0.1 and 20 microns of particles that remain windborne unless they are deposited by the rain or by their weight, according to Science Daily.

Different meteorological phenomena could affect the emission and transport of African dust, such as El Niño, the North Atlantic Oscillation, rainfall in the Sahel region, the Sahara Heat, and the Intertropical Convergence Zone. The Dispersal of African dust depends on the strength of the Saharan winds called Harmattan, wherein high speeds could blow over dust source regions.

Scientists try to understand these complex relationships in nature by using statistical analysis of data from the 20th century and combine it with the study of dust deposits in the coral reefs in Cape Verde, and the wind data used to eliminate fluctuations in dust emissions since the 1850s. Results of their study were applied to future climate projections to establish trends until the end of the 21st century.