Featured Research

from universities, journals, and other organizations

African Dust Storms May Cool Atlantic, Lessen Hurricanes

Date:
February 20, 2008
Source:
University of Wisconsin-Madison
Summary:
Every year, storms over West Africa disturb millions of tons of dust and strong winds carry those particles into the skies over the Atlantic. According to atmospheric scientists, this dust from Africa directly affects ocean temperature, a key ingredient in Atlantic hurricane development.

An image, captured on Sept. 4, 2005, by the Moderate Resolution Imaging Spectroradiometer aboard NASA's TERRA satellite, shows a massive dust storm (in yellow) blowing off the western coast of Africa over the Atlantic Ocean. Amato Evan, a researcher at the UW-Madison Cooperative Institute for Meteorological Satellite Studies, has found a surprising link between hurricane frequency in the Atlantic Ocean and dust storms that periodically rise up from the Sahara desert and move west. Evan and others suggest that such atmospheric dust could be helping to "dampen" brewing hurricanes.
Credit: NASA/courtesy Amato Evan

Every year, storms over West Africa disturb millions of tons of dust and strong winds carry those particles into the skies over the Atlantic. According to a recent study led by University of Wisconsin-Madison atmospheric scientists, this dust from Africa directly affects ocean temperature, a key ingredient in Atlantic hurricane development.

Related Articles


"At least one third of the recent increase in Atlantic Ocean temperatures is due to a decrease in dust storms," says lead author Amato Evan, a researcher at UW-Madison's Cooperative Institute for Meteorological Satellite Studies (CIMSS).

In a paper published online in "Geochemistry, Geophysics, Geosystems," the team of scientists 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 by co-author Andrew Heidinger, a researcher with the National Oceanic and Atmospheric Administration (NOAA), Evan assessed how much the dust cooled the temperature of the ocean.

"It's not just one dust storm," Evan says. "It's the cumulative effect of several months of dust storms."

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. 2007 was the dustiest year since 1999.

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.

In a study published in fall 2006 in "Geophysical Research Letters," Evan demonstrated that the intensity of hurricane seasons in the Atlantic increased when the amount of dust blowing off of Africa decreased and vice versa. The study published today is an effort to explain why this relationship exists and what the past few decades would have looked like without the effects of dust. Evan says 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," Evan says. Evan has done some preliminary work to develop an effective way to use satellite observations to predict dust activity up to nine months in advance.

Dust storms in Africa have a significant impact on the temperature of the Atlantic Ocean, which, in turn, plays a large role in hurricane activity. Although climate change has taken the spotlight in media conversations about hurricanes, many factors influence these complicated storms. Of the effects of global warming, Evan says: "It's real, but that's not all there is."


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. Note: Materials may be edited for content and length.


Cite This Page:

University of Wisconsin-Madison. "African Dust Storms May Cool Atlantic, Lessen Hurricanes." ScienceDaily. ScienceDaily, 20 February 2008. <www.sciencedaily.com/releases/2008/02/080215191428.htm>.
University of Wisconsin-Madison. (2008, February 20). African Dust Storms May Cool Atlantic, Lessen Hurricanes. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2008/02/080215191428.htm
University of Wisconsin-Madison. "African Dust Storms May Cool Atlantic, Lessen Hurricanes." ScienceDaily. www.sciencedaily.com/releases/2008/02/080215191428.htm (accessed October 26, 2014).

Share This



More Earth & Climate News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins