In addition to those troublesome low pressure tropical waves bring downpours, Africa also contributes large quantities of dust to the Caribbean and Costa Rica.
A new study at the University of Miami, Florida, verifies this and says that the Caribbean Basin receives enormous quantities of African dust every year. In addition to its impact on air quality, an important factor for the Caribbean basin is the potential effect of Saharan air outbreaks on hurricane activity, the study said.
The findings published in the journal of Environmental Science and Technology.
Joseph Prospero, professor emeritus at the university, found that the average air concentrations of inhalable particles more than doubled during a major Saharan dust intrusion in Houston, Texas, said the university, adding that:
The researchers were able to distinguish between particles transported across the Atlantic and those from local sources in the Houston region. In this way they established the fingerprint of the African dust. To their knowledge, this is the first study that isolates, differentiates, and quantifies the air contaminants in the U.S. during the incursion of African dust. There is a concern that the fine airborne dust particles could be a health problem for asthmatics and people with respiratory problems.
The presence of dust from Africa has been reported in Costa Rica, but there have been no measurements of quantity.
“African dust storms are associated with hurricane season because the meteorological situations that are involved with generating tropical cyclones are also associated with the generation and transport of dust,” Prospero said in a university release. “The dust emerges from the coast of Africa in a hot, dry, elevated layer, the Saharan Air Layer, following behind easterly waves from which tropical cyclones sometimes develop.”
The dust suspended in the wind absorbs and scatters solar radiation, so less sunlight reaches the ocean surface resulting in cooler temperatures in the tropical Atlantic Ocean, the main area where hurricanes develop, he added. Cooler ocean temperatures mean less energy for hurricanes to form and strengthen, he noted.
“Dust activity has been very intense this year and sea surface temperatures are unusually low,” Prospero said in the release. “These may have been contributing factors to the unusually weak hurricane season this year.”