Dust storms affect hurricane activity (Merged)

[Daisy]

Anyone seen this article from the BBC?

Dust storms affect hurricane activity

Thought it was quite interesting

Regards,

D

[Crepuscular Ray]

Yes, it was very interesting. In the immediate sense, it would be fascinating to compare the different amounts of dust this year and last, given the vast differences in tropical storm numbers.

[Lincs Observation]

this is my 1200 and my elevation to a cumulonimbus and i came across this gem to post, have a read its very interesting.

US researchers have discovered a link between Atlantic hurricane activity and thick clouds of dust that periodically rise up from the Sahara Desert.

At times of intense hurricane activity, dust clouds were scarce, but in years with stronger dust storms, fewer hurricanes swept across the Atlantic.

The work raises the tantalising possibility that Saharan dust storms could help to quench hurricanes.

Details appear in the scientific journal Geophysical Research Letters.

"These findings are important because they show that long-term changes in hurricanes may be related to many different factors," said co-author Jonathan Foley, director of the Center for Sustainability and the Global Environment at the University of Wisconsin-Madison.

"While a great deal of work has focused on the links between [hurricanes] and warming ocean temperatures, this research adds another piece to the puzzle."

Dust tracking

Researchers have increasingly turned their attention to the environmental impact of dust, after it became clear that, in some years, millions of tonnes of sand rise up from the Sahara Desert and travel across the Atlantic Ocean - sometimes in as little as five days.

If scientists conclusively prove that dust storms help to suppress the development of hurricanes, weather forecasters could one day begin to track atmospheric dust, factoring it into their predictions for the first time, the researchers say.

Hurricanes: Animated Guide The Saharan sand rises when hot desert air collides with the cooler, drier air of the Sahel region, just south of the Sahara.

The windy conditions that result toss the sand upwards. Then, strong trade winds begin to blow them westward into the northern Atlantic Ocean.

Dust storms form primarily during summer and winter months, but in some years, for reasons that are not understood, they barely form at all.

The researchers say that dry, dust-ridden layers of air probably help to "dampen" brewing hurricanes, which need heat and moisture to fuel them.

But co-author Christopher Velden, from the University of Wisconsin-Madison, said that effect could also mean that dust storms had the potential to shift a hurricane's direction further to the west, which means it would have a higher chance of hitting the United States and Caribbean islands.

"What we don't know is whether the dust affects the hurricanes directly, or whether both [dust and hurricanes] are responding to the same large-scale atmospheric changes around the tropical Atlantic," said Dr Foley. "That's what future research needs to find out." The study was funded by the US National Oceanic and Atmospheric Administration (Noaa).

Source BBC Space and Technology & NOAA

LO

Edited October 15, 2006 by Luton Observation

[Lincs Observation]

Popping this into the hurricane forum :o

THX Wibs wondered where to put it .

LO

[johnholmes]

interesting idea, and one I've not heard of before.

[SP1986]

I disagree....because dust can make it into any airmass and more often than not rains in the UK will leave dust traces in wake of SE'ly winds from rain/thunderstorms for example in the case of dust, moisture forms around dust particles in thunderstorms, and we know that Hurricane layouts are made entirely of smaller cumulonimbus cells around the outer rim of the hurricane, whilst larger cumulonimbus cells act in the centre... often moisture that forms around dust will either fall as very large drops of precipitation due to the ionic properties within the dust, these attract water droplets, or instead hail, due to the same principle. However to prove such claims evidence in form of calculus really is needed!

I can see where the argument comes from but I cant personally see that just because sand travels (possibly in a dry airmass, it surpresses hurricanes)

Its one of those questions though for and against!!

[Gray-Wolf]

From the SAL this year it has been the combo of dry and dust that has , once ingested, caused major problems within the forming systems (IMO).

[kold weather]

It's not so muc hthe dust itself that prevents tropical waves from developing further much like this year but the actual properties of the Sahara itself.

Afterall its a desert and deserts are well known for being dry as we all know.

The problem for tropical waves coming off Africa is that quite often they find themselves with a large inflow but not in the right direction so instead of taking in nice moisture laden air from the sea they take it in from elsewhere. Because these waves move generally from east to west and in this hemisphere usually a storm will take in air from the east on its northern side it take sin the much drier airmass from the Sahara and with it the dust is taken from the desert and out to see. SAL is usually simply the result of the LP/wave moving out into the Atlantic.

The injestion of the dry air also explains why you tend not to see these hurricanes from this part of the world till August, because until that time the Inter tropical convergance zone is too far south, so any wave injests the very dry air, and its not until the seas warm up even more and the T-storms get stronger with more heat plus the movement northwards of the ITCZ allows systems to finally get going.

Ironically last years strong hurricanes such as Katrina were in large part to be blamed by this dry airmass as it caused systems to develop much further west in even more favorable waters, tohugh 2005 was a very complicated season with many facotrs going perfectly. For you winter lovers, think of it as a 62-63, evryone came together to pull off one hell of a season.

One other thing, this has got some evidence as there was a bunch of people down in the Cape verde islands who flew many many times into tropical waves to see how the structure is affected by this dry aitr mass for a about 2 months this summer.

Edited October 22, 2006 by kold weather