Cape Verde Hurricane Mitigation by Surface Albedo Enhancement

Gaskill gave a brief presentation of how the number of Cape Verde hurricanes could be reduced by applying the GAEP to selected areas of the Sahara desert.

He said that although tropical storms and hurricanes can form in a variety of ways, tropical waves are the most common. They begin as disturbed areas of wind flow or cloud clusters. One area from which such disturbed air masses originate is the southwestern Sahara desert. When these disturbed air masses enter the Atlantic Ocean, they can progress to form tropical waves, tropical depressions, tropical storms and then hurricanes. These storms are then sometimes referred to as Cape Verde hurricanes, since they pass near the Cape Verde Islands.

Because tropical waves that form Cape Verde hurricanes may have several weeks to develop as they cross the Atlantic, they have the greatest potential to grow into Category 5 storms, the most dangerous and destructive. The Cape Verde storms are nearly 85% of the most intense Atlantic hurricanes. A relevant example is Hurricane Andrew in 1992.

Gaskill said there is limited evidence that future warming in this region of the Sahara will lead to increased water vapor levels and more tropical waves. By raising the albedo of the southwestern Sahara, the evaporation rate for precipitation in this region may be decreased, lowering the water vapor level in the atmosphere and decreasing or at least not increasing the number of tropical waves produced. The surface coverage may also change the direction of wind flow in the area and prevent the formation of tropical waves altogether, removing an annual threat to the Caribbean and mainland U.S.

For these reasons, Gaskill said climate modeling of this specific application of the GAEP should be performed.