Suppose this could go in the volcano thread, but it
is atmospheric: an image from
STS-43 on August 8, 1991, that I've been looking for for a while.
Dr. Clive Oppenheimer used it in his book
Eruptions That Shook The World, and described it as a double layer of sulfate aerosol that formed in the stratosphere after the climactic eruption of Mount Pinatubo on June 15, 1991, sent an estimated 18 megatonnes of sulfur sky-high, which then reacted with water to form LOTS of tiny sulfuric acid droplets that didn't totally disappear for about three years.
The irregular dark clouds are tops of big thunderstorms -- not sure where, possibly Africa.
Lots of satellite, high-altitude flight, and ground-based data on that eruption.
Per Oppenheimer, by August 1991 the planet's albedo had increased about 5% from aerosol reflecting (it also warms up the stratosphere by absorbing IR from Earth), and for two years Pinatubo's negative climate forcing exceeded positive forcing from manmade greenhouse gases.
The general pattern from an aerosol layer like that is summer cooling and winter warming. The global average cooling was 0.5° C, but regions of increased warming or cooling occurred. Siberia's winter was about 5° C warmer, and the North Atlantic 5° C cooler.
All this according to Dr. Oppenheimer, who also notes a significant drop in rainfall over land but with strong regional patterns, including one of the coldest, wettest summers of the 20th century for the US in 1992 and drought in central/southwestern Europe and much of sub-Saharan Africa.