Mechanism and Force Driven Asian Dust Storm - PowerPoint PPT Presentation

Title: Mechanism and Force Driven Asian Dust Storm


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Mechanism and Force Driven Asian Dust Storm

• Wang Guo
• Institute of Geographical Sciences and Natural
  Resources Research, Chinese Academy of Sciences,
  No. 3, Datun Road, outside Andingmen, Beijing
  100101,People's Republic of China
• Email wg699_at_hotmail.com

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1. Modern Sources of and Paths Asia Dust storm

• (1) Favonian Dust storm
• The dust storm covers from Asia to the
• Midwest of America.
• (2) Subtropical Dust storm
• It covers circum-Mediterranean Sea

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This SeaWiFS image show the development of a
large dust storm in Asia and its interaction with
a meteorological system that carried the dust far
out into the Pacific Ocean. From April 16, 1998,
the bright yellowish-brown cloud near the coast
is the center of the storm, being pushed by a
frontal system. April 20-24, the atmospheric
circulation around a low-pressure system entrains
the dust from the storm and carries it over the
north Pacific Ocean.
One of Sources of Favonian Dust storm
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SeaWiFS image of the west coast of North America
on April 25, showing the arrival of airborne dust
from Asia. The dust is visible in the clouds at
the center of the left edge of the image, and as
streaks of light brown haze over Cape Mendocino
on the California coast.
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(a) China, April 17, 2001, as captured by SeaWiFS
(b) Japan, April 17, 2001, as captured by SeaWiFS
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Duststorm over America
(a) San Diego, California, on January 3, 2001, as
captured by SeaWiFS
(b) Superior, April 17, 2001, as captured by
SeaWiFS
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The Middle East Dust Storm, May, 20, 1999, from
SeaWiFS
The large dust storm off of North Africa on April
18th 2001.
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Upper Lift On the Coast of West Africa, dust
storms, Feb. 26, 2000 from SeaWiFS Right the
large dust storm off the coast of North Africa on
July 18th 2000
Upper Right This SeaWiFS image clearly shows a
massive dust storm over Libya. The image was
taken on August 23, 2001
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2. Favonian Floating Dust Change over China in
the last 50 Years

• (1) Change in Space-time
• The Floating Dust in China prevailed in
  1950s -1970s, began to weaken in 1980s. And it is
  small since 1990s .
• (2) Nationwide Trendline in Time
• Days of Dust storm is decreased in China since
  1954.

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Change of Days of Dust storm in China from 1954
to 2001
The total trence is decrease, Dust Storm Maximum
is in 1666
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2. Dust Storm Change over China in the last 1700
Years

• There are 5 activity periods of dust storm in
  China, 1060-1090, 1160-1270,1470-560,1610-1700,182
  0-1890 since AD. 300

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3. Dust Storm Change over China in Quaternary

• Loess sediment in China occur in glacial,
  paleo-soil develop in interglacial.

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4. Onset of Asian desertification by 22 Myr ago
inferred from loess deposits in China Dust
accumulation rate (DAR) in northern China. Data
for 06.2 Myr interval are calculated based on
the loesssoil sequence and the Hipparion
Red-Earth formation at Xifeng. It show that the
loess sedmentary rate in cold period is greater
than in warm period. (from Nature, 416, 159 -
163, 2002 )
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5. Dust Storm in China and Cooling

1. On scale of 50 years 1960s,1970s
2. On scale of 1000 years little glacial
3. On scale of 2Ma glacial loess
4. On scale of 22Ma the high sedimentary rate in
   the last 3Ma.

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6. Conclusion

1. Asia Dust storm driven by climatic system. Dust
   storm in Asian westerlies relate to cool.
2. Human activity dont play a important role on
   Asia Dust storm.

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• Thank You