An Introduction to Environmental Chemistry

Plate 6.2

Global composite image of optical depth (tau units) in the Earth’

s atmosphere for June–August 1989–1991. Optical depth data

provides a measure of aerosol concentration. Reproduced from Husar RB, Prospero JM and Stowe LL (1997)

Journal of Geophysical

Research

102, 16889–16909, copyright by the American Geophysical Union.