Space shuttle crews see a sunrise or sunset every 45 minutes as they circle the Earth at 17,000 miles per hour, crossing the surface at four miles per second. From their unique perspective they see clearly defined bands of color through the atmosphere as the Sun rises. High-peaking cumulus clouds, topping out in anvil-head cirrus, can be seen as black shadows against the sunlit horizon. The brightness of the colors in the atmosphere in this photograph taken over the South China Sea is due to concentrations of dust in the atmosphere. Greater concentrations of dust are found in equatorial regions. There are various sources for such upper level dust Many dust storms in Africa, intensified by several years of drought, have been responsible for putting large amounts of dust into the atmosphere in recent times. Ash clouds from major volcanic eruptions can have a similar effect. Recent discussion of the climatic and environmental effects of a “nuclear winter” centering on upper atmosphere pollution has drawn from the atmospheric effects of catastrophic volcanic eruptions.
41-D, August-September 1984. Picture #14-32-014.