Posted on 08/17/2005 9:34:07 AM PDT by jb6
(Miami-AP) July 23, 2005 - A dust cloud nearly as big as the continental United States is heading toward the southern states. It's expected to move across Florida sometime between Monday and Wednesday.
The dust blowing in from the Sahara Desert is expected to spark colorful sunrises and sunsets. A spokesman for the Broward County Environmental Protection Department says if people subject to respiratory conditions see hazy skies, they may want to take a pass on strenuous activity and stay indoors.
"This is not going to be a tremendous event, but it will be kind of interesting," said Jim Lushine, a severe weather expert with the National Weather Service in Miami.
Such dust clouds are not uncommon, especially at this time of year. They start when weather patterns called tropical waves pick up dust from the desert in North Africa, carry it a couple of miles into the atmosphere and drift westward.
It's not expected to be seen north of Florida or south Texas. 
Born on a parched African plain, it loops and swirls across the Atlantic each spring, leaving a film of microscopic dust over everything it passes: islands, rain forests, huts, mansions. Once again the red wind is blowing, and this year it is especially fierce.
Scientists know the phenomenon as aeolian, or atmospheric, dust. It mystifies and annoys those who live along its routes—which extend over much of the globe—and has been blamed for a plethora of ill effects including coral bleaching and even human disease.
Dust from the Sahara blows out over the Atlantic. This satellite image was taken on June 22, 2000.
“It’s been an unusually active year for dust coming out of Africa,” says Joseph M. Prospero, a University of Miami atmospheric and marine chemist who has studied the phenomenon for more than three decades. “We’ve had spectacular dust outbreaks starting in late February. I haven’t seen anything like this in many years.”
Dust pollution occurring near the source of an African outbreak has been known to contaminate food and drinking water, cause highway accidents, close airports, disrupt radio and satellite communications, and even suffocate cattle.
Borne aloft by trade winds, the heavier particles quickly drop away. Those that survive the journey across the ocean are a hundred times smaller than the diameter of the finest human hair. The dust normally arrives in the Caribbean by mid-June, as reliable as an unwelcome house guest, and doesn’t leave until fall. Islanders see the results most vividly at sunset: the opalescent glow that ordinarily lights the sky in these regions becomes a muddy shade of burnt orange.
“BLOOD SNOWS”
At various times dust from Africa can be found as far west as South America and as far north as central Europe, where it is blamed for “blood snows” in the Alps and Pyrenees.
“It originates wherever there is a desert,” says Lester Machta, of the National Oceanic and Atmospheric Administration (NOAA). “When strong winds occur, they just pick up the dust and carry it along. Most of it falls out over the water, but enough comes across to be detectable.”
Africa isn’t the only source. Springtime windstorms in western and central China pick up large quantities of yellow dust and deposit them across Japan, especially in the south, where they’re called “kosa.” Particles that bypass Japan scatter across the Pacific Ocean to destinations as far north as the Bering Strait between Alaska and Siberia, and as far south as the Antarctic Circle.
Using thermal channel differencing techniques, dust blowing from China across the Huang Hai is clearly visible. This satellite image was taken on May 4, 2000
Saharan dust periodically prompts the National Weather Service Office in San Juan, Puerto Rico, to issue an air pollution alert. Thomas Cahill of the University of California at Davis recently has found traces of Saharan dust in the Southeast and Eastern United States.
“When the dust comes up here to Miami, which is not as often as farther south, it is pretty dramatic,” says the University of Miami’s Prospero. “The visibility may be reduced to five or six kilometers, and if it rains, we get mud spots on our cars. It is not a subtle change.”
Prospero, who monitors dust through a network of air-sampling stations in both the Atlantic and Pacific, says that by the time the particles reach the United States, for the most part they have lost their harmful properties.
GULF WAR SYNDROME CULPRIT?
Dust outbreaks are likely to be most harmful close to the source. Airborne dust is one of the suspected culprits in the range of maladies labeled “Gulf War Syndrome” resulting from the 1991 U.S.-led military campaign in Kuwait. Roland Draxler of NOAA’s Air Resources Laboratory estimates that roughly 30 percent of the surface of Kuwait was disturbed by the war, resulting in higher than usual levels of dust.
Wind patterns send dust across the African coast into the Red Sea. This satellite image was taken on June 27, 2000.
However, some scientists theorize that aeolian dust may have beneficial effects. Since the particles are chemically alkaline, they may dilute sulfuric acid—a major component of acid rain. They might even be helping to offset the current trend toward global warming. (See sidebar.)
Dust can make noticeable differences in weather. In a process similar to the formation of acid rain clouds from industrial air pollutants, airborne moisture may form around the tiny particles, which become cloud droplets. The chemistry of the resulting rainfall depends on the composition of the particles that made the cloud.
An obvious question is whether human activities such as deforestation and other disturbances of the land have increased the levels of aeolian dust on a global basis. Although some scientific models in specific areas have shown as much as a 50 percent increase in dust resulting from human impacts, Prospero isn’t prepared to make any global generalizations.
“The surface of the earth is very mobile,” he says. “The continents move around, materials are moving around. Dust is another manifestation of the dynamic nature of the earth.”
http://news.nationalgeographic.com/news/2000/07/0710_dust.html
I swear it wasn't me!
Will it keep hot temperatures down??
July 23, 2005 - arrive between Monday and Wednesday (July 25-27)
A bit dated, no?
"They might even be helping to offset the current trend toward global warming."
So, deforestation, purportedly a cause of "global warming," and desertification, purportedly an effect of "global warming," also produce dust clouds which mitigate "global warming."
But, we still need world socialism to save us all from "global warming?" Oh, right, it's "climate change" now. Can't be limited to warming or cooling, when it comes to using an unpredictable, chaotic system as a propaganda tool to further world socialism, now can we? That just wouldn't do.
Great pics, btw.
So?
This already happened. It was a bit hazy, but no significant weather changes so far as I could tell here in Daytona, FL.
Bush's fault ....
Heading right at Florida.
These dust clouds carry viruses, toxins, plant eating bugs, and all kinds of nasty cooties.
It's TEOTWAWKI, I tell ya....
Wasn't there a plankton bloom last week?
"plant eating bugs"
I'd much prefer bug eating plants, myself.
http://www.usatoday.com/weather/news/2004-07-06-hurricanes-plankton_x.htm
The stronger the storm, the larger and longer the bloom of plankton, he said.
These tiny plants grow in great numbers when they bloom, absorbing carbon dioxide from the atmosphere. When they die they sink to the bottom, trapping the excess carbon for thousands of years
And, he added, there is a competing effect, because when the storms toss the sea around the water can release dissolved carbon dioxide, somewhat like a shaken can of soda loses its fizz.
It's not known whether the two effects balance out or if the plankton helps reduce gasses in the air, Babin said.
Has the EPA been alerted? They should regulate this and ban it, with economic sanctions.
OK! Karl Rove made me do it!
There is some kind of plankton bloom in the Gulf of Mexico, red tide or something. A few complaints are drifting in to authorities, although what authorities might do about it is questionable. Maybe just make a note.
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