In recent weeks, Texas and parts of the southeastern U.S. have found their sunny summer sky dimmed – not by clouds, but from Sahara dust blown over the Atlantic Ocean.
The intercontinental dust bowl has blown anywhere from 2 to 9 trillion pounds of desert dust from North Africa to the Gulf of Mexico and surrounding area.
The gloomy dust cloud may have a silver lining, though. All that sand and grit seems to be putting a serious damper on hurricane season.
“Dust may decrease the sea surface temperature, leading to suppression of hurricanes. For the dust intrusion over the past few days, it was obvious that dust suppressed cloud formation in our area,” said Dr. Renyi Zhang, who co-authored the study with Texas A&M University colleagues Bowen Pan and Tim Logan.
By analyzing satellite imagery and data from NASA, the trio was able to determine that the Sahara dust – more accurate, a mixture of desert sand and mineral particles – is creating a temperature inversion as it is carried high into the air by wind.
The dust reflects and absorbs sunlight when it’s high in the atmosphere, cooling ground-level temperatures. However, the minuscule particles also heat up, warming temperatures high above the ground. This seems to create a more stable atmosphere and prevent clouds from forming, Zhang said.
If the international dust devil lasts, it could quash some hurricanes and keep others from becoming severe, the researchers theorized. Dust is continuing to move into the Gulf of Mexico region, but dust storms can be challenging to predict, Zhang noted.
“If we have more frequent and severe dust storms, it’s likely that we have a cooler sea surface temperature and land surface temperature,” Pan said. “The storms have less energy supply from the colder surface therefore will be less severe.”
Their study has been published in the Journal of Climate. Research funding was provided by NASA, the California Council on Science and Technology, and the Jet Propulsion Laboratory.
By Kyla Cathey, Earth.com staff writer