Aerosols may weaken hurricanes and cyclones

Aerosols in the atmosphere produced from human activities such as from factories and cars tend to weaken hurricanes or tropical cyclones, a new study has claimed.
Researchers including a team of Texas A&M University found that aerosols do indeed directly affect such storms, but not in a way many scientists had previously believed.
Renyi Zhang and colleagues examined how anthropogenic aerosols - those produced from human activities, such as from factories, power plants, car and air-plane emissions and other forms - play a role in the development of hurricanes.
The team used a complex computer model and data obtained from Hurricane Katrina, which struck the Gulf Coast in 2005 and produced catastrophic damage.

The researchers found that aerosols tend to weaken the development of hurricanes (tropical storms that form in the Atlantic Ocean) or typhoons (those formed in the Pacific).
They also found that aerosols tend to cause a hurricane to fall apart earlier and wind speeds are lower than storms where anthropogenic aerosols are not present.

On average, there are about 90 hurricanes or cyclones that form each year around the world, meaning the findings could be crucial in how we evaluate and prepare for destructive tropical storms, researchers said.
"The results are surprising because other studies have leaned the other way - global warming by greenhouse gases makes hurricanes more intense and frequent. We found that aerosols may operate oppositely than greenhouse gases in terms of influencing hurricanes," Zhang said.

"Another thing we find, however, is that aerosols appear to increase the amount of precipitation in a hurricane or typhoon. The rain-bands associated with such tropical storms seem to be larger and stronger," said Zhang.
Zhang said the results could prove beneficial in how future hurricanes are studied - and how important the presence or absence of aerosols impact the development of such storms.
"The information produced from this study could be very helpful in the way we forecast hurricanes," Zhang said.
The study was published in the journal Nature Climate Change.