Plenty of the dust that affects Costa Ricans has come a long way. Africa contributes massive quantities of dust to the Caribbean and Costa Rica.
A study at the University of Miami, Florida, verified 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 emission and transport of this dust, which can reach the poles, fluctuate considerably. Although many hypotheses have been put forward to explain this phenomenon, no unambiguous relationship between this dust and the climate had been established until now, according to the Centre National de la Recherche Météorologique.
A U.S. and French team reported last week that meteorological events such as El Niño and rainfall in the Sahel have an impact on dust emission, by accelerating Saharan wind downstream of the main mountain massifs of Northwest Africa. The scientists have also developed a new predictive model showing that emissions of Saharan dust will decline over the next hundred years, said the Centre.
Emission and dispersion of the dust is affected by a number of meteorological phenomena, such as El Niño, the North Atlantic Oscillation, rainfall in the Sahel, the Sahara Heat Low, and the Intertropical Convergence Zone, the Centre’s summary of the research says, adding:
The researchers carried out a statistical analysis of reconstructed 20th century data of winds and dust deposits
in the coral reefs of Cape Verde. The wind data were used to estimate fluctuations in dust emissions since the 1850s.
The results obtained reproduce several well-known events, showing that the North Atlantic Oscillation caused important dust emissions in the years 1910-1940, as did the Sahel drought of the 1980s.
Since this method successfully reproduced past events, it was then applied to future climate projections with the aim of establishing trends until the end of the 21st century. The method predicts a decrease in dust generation. Although this could have beneficial effects on the health of human populations, it might also increase warming of the tropical North Atlantic, making it more suitable for hurricane formation and growth.