Posted on 02/20/2008 2:57:12 PM PST by blam
African Dust Storms May Cool Atlantic, Lessen Hurricanes
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)
ScienceDaily (Feb. 20, 2008) — 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.
List of major natural disasters in the United States National Hurricane Center Great Hurricane of 1780 "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."
Adapted from materials provided by University of Wisconsin-Madison.
It’s complicated. This whole global warming scam needs to be tended continuously. You don’t want al gore to lose money do you?
Bushes fault!
Global Warming strikes again!
Damn. That global warming beast rears it’s ugly head again. /sarc
HURRICANE DENIER!
It’s GLOBAL DUSTING!
Isn’t it those low pressure systems coming off the African coast that spawn Cape Verde Hurricanes?
I’m guessing the dust induces cloud formation which then reflects solar energy back out to space. Clouds have great influence on the weather. The GWers are loath to mention this because we can make our own clouds.
As a resident of S. Florida I say - more dust storms, more dust storms!
Click on POGW graphic for full GW rundown
New!!: Dr. John Ray's
GREENIE WATCH
The Great Global Warming Swindle Video - back on the net!! (click here)
Ping me if you find one I've missed.
LOL! Laborers in the kitchen garden of Anthropogenic Global Warming, singing happily as they pull up the Weeds of Disbelief...
Why do it?
Sarcasm is a lost art.
{lightin up, bro.}
Unless you haven’t noticed, its a little game we play. We are pokeing fun at the climate change chicken littles.
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