Global Visibility: Regional and Seasonal Pattern Janja D. Husar and Rudolf B. Husar CAPITA, Washington University, St. Louis, MO HTTP\CAPITA\CapitaReports\GLOBVIZ\GLOBVIS1.html

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

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

Approach Exploration of extinction coefficient seasonality in different regions of the world. Delineate a region by its topography and/or Look for similarity in seasonal trend

Extinction Coefficient Contours, km-1, High bext (>0.5km-1) India: year round; Indonesia: fall; W. Africa: winter; Bolivia: fall

Du Xinli Shaanxi Institute for Environmetnal Research and Design Xi’an, China

Asia, Far East (China)

More about dust storms in China

Western China: Desert regions north of Tibet (Xizeng), Xinjiang province : Spring peak: Higher bext in the foothills of Tibet than in the north

Western China, Spring 1996, highly episodic, episodes coincide over vast territory of western China

Western China, Tibet and Gobi Spring peak : Episodic, lower bext than in Xinjiang province

Western China, Tibet and Gobi Winter low and few episodes; Spring slightly higher and some episodes

Eastern China, North

China, Sichuan and Shaanxi provinces Enclosed industrial basins in the central part of China, winter peaked

China, Harbin in the north and Nan-ning in the south

Indian subcontinent, about 100 monitoring stations

Visibility-Population Density Comparison In India bext and population density compare OK

Indian subcontinent

India Desert

Satellite AVHRR optical depth data over the oceans RB Husar et al., 1997, JGR, 102, Note extent and magnitude of elevated optical depth: Winter and Spring: western Africa and China Summer and Fall: northern western Africa and equatorial Africa

Africa vegetation map

Africa, western, tropical forest-savanna Mali to Benin, winter peak

Africa, western; Sahara southern part. Winter peak still present, however spring peak appears

Africa, western; equatorial. Summer peak

South America Forests And September Fires

South America, Bolivia

Global aerosol jigsaw puzzle Fuse information, collect available aerosol measurements