Global Visibility: Regional and Seasonal Pattern

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Global Visibility Regional and Seasonal Pattern

• Janja D. Husar and Rudolf B. Husar
• CAPITA, Washington University, St. Louis, MO
  63130-4899
• HTTP\CAPITA\CapitaReports\GLOBVIZ\GLOBVIS1.html

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QuestionsRole of aerosols in global warming.
Is there a singular background aerosol or
background aerosol is regional. Role of
anthropogenic aerosol vs background
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Visibility data

• Surface observations.
• Over 8000 stations' throughout the six
  continents.
• The on line data files presented
• January, 1994 through October 1997.

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ApproachExploration of extinction
coefficient seasonality in different regions of
the world.Delineate a region by its
topographyand/orLook for similarity in
seasonal trend
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Extinction Coefficient Contours, km-1,High bext
(gt0.5km-1) India year round Indonesia fall
W. Africa winter Bolivia fall
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Du Xinli Shaanxi Institute for Environmetnal
Research and DesignXian, China
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Asia, Far East (China)
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More about dust stormsin Chinahttp/Capita.wustl
.edu/Asia-/FarEast/home.html
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Western China Desert regions north of Tibet
(Xizeng), Xinjiang province Spring peak Higher
bext in the foothills of Tibet than in the north
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Western China, Spring 1996, highly episodic,
episodes coincide over vast territory of western
China
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Western China, Tibet and GobiSpring peak
Episodic, lower bext than in Xinjiang province
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Western China, Tibet and GobiWinter low and few
episodes Spring slightly higher and some episodes
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Eastern China, North
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China, Sichuan and Shaanxi provincesEnclosed
industrial basins in the central part of China ,
winter peaked
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China, Harbin in the north and Nan-ning in the
south
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Indian subcontinent, about 100 monitoring
stations
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Visibility-Population Density ComparisonIn India
bext and population density compare OK
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Indian subcontinent
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Indian subcontinent
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India Desert
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Satellite AVHRR optical depth data over the
oceansRB Husar et al., 1997, JGR, 102,
16889-16909. Note extent and magnitude of
elevated optical depthWinter and Spring
western Africa and ChinaSummer and Fall
northern western Africa and equatorial Africa
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Africa vegetation map
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Africa, western, tropical forest-savannaMali to
Benin, winter peak
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Africa, western Sahara southern part.Winter
peak still present , however spring peak appears
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Africa, western equatorial.Summer peak
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South America Forests And September Fires
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South America, Bolivia
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South America, Bolivia
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Global aerosol jigsaw puzzle Fuse information,
collect available aerosol measurements