Washington, Feb 17 : A new study has indicated that strong winds from Western Africa carry dust particles into the skies over the Atlantic Ocean, directly cools down the ocean temperature, leading to lesser hurricane development in the region.
Atmospheric scientists from the University of Wisconsin (UW) - Madison conducted the study.
"At least one third of the recent increase in Atlantic Ocean temperatures is due to a decrease in dust storms," said Amato Evan, a researcher at UW-Madison's Cooperative Institute for Meteorological Satellite Studies (CIMSS).
According to the team of scientists, the study describes how dust in the atmosphere cools the ocean by decreasing the amount of energy that reaches the water.
The study also demonstrated that the large amount of dust blowing off of Africa in the 1980s and '90s likely cooled the Atlantic enough to prevent conditions that could have resulted in more devastating hurricane seasons similar to 2004 and 2005.
As dust from Africa accumulates in the skies over the Atlantic, the atmosphere above the ocean begins to resemble the conditions over Africa. Millions of tons of dust create a drier environment and also reduce the amount of sunlight that reaches the ocean.
Using a 25-year data record created a researcher with the National Oceanic and Atmospheric Administration (NOAA), Evan assessed how much the dust cooled the temperature of the ocean. By putting satellite observations and other atmospheric information into a computer simulation, Evan assessed how much energy reached the ocean with the dust in the atmosphere and then again after removing the dust.
Evan found that dust cools the Atlantic by an average of one degree Celsius, about two degrees Fahrenheit, each year.
In years with a lot of dust activity, such as the 1980s, the dust had a larger cooling effect.
"It's not just one dust storm," said Evan. "It's the cumulative effect of several months of dust storms," he added.
The 2007 Atlantic hurricane season, for example, was much quieter than predicted and the Atlantic was cooler than in previous years. Evan suggests that the relative lack of hurricane activity and cool ocean temperatures could be partially due to a particularly dusty spring and early summer. According to Evan, these results confirm a direct connection between the intensity of dust storms in Africa and that of hurricanes in the Atlantic. Because of the direct relationship, the amount of dust in the atmosphere could contribute to hurricane season forecasts.
"Dust prediction is another tool to diagnose hurricane activity," said Evan.