Volcanic eruptions can offer a spectacular and very dangerous scene as they spew millions of tons of ash into the atmosphere. We have all seen classic images of a volcano erupting, but what happens to the ash after it is sent hurtling into the atmosphere??? Below is an image taken by a NOAA satellite that shows several plumes of sulphur dioxide streaming across southern Canada and the northern border of the United States. This sulphur dioxide (indicated by the yellow SO2 symbols) likely came from a volcanic eruption in the Kuril Islands south of Kamchatka, Russia in late June. It is not uncommon for volcanic ash to travel thousands of miles after it suspended in the atmosphere.
Picture courtesy of: NOAA
According to NOAA's Earth Systems Research Laboratory (ESRL), Benjamin Franklin was the first person to suggest that major volcanic eruptions could emit enough ash and other particles into the atmosphere and that it could have a significant impact on short-term climate, even great distances from where the eruption occurred. How would this occur? Volcanic debris that is thrust into the troposphere and stratosphere can actually remain for months, up to a few years. This debris, like the sulfuric acid pictured above, turns into tiny droples of sulfuric acid in time. These sulfuric acid droplets are responsible for having an effect on climate because they can block incoming solar radiation from entering Earth's lower atmoshpere, cooling the earth. Also, a warming component can exist as outgoing radiation from the earth is blocked by the acid particles. This warming component has a lesser effect on climate change than the cooling component and is a similar process to the warming feature referred to as "The Greenhouse Effect". Obviously, cooling or warming of the earth will change thermal patterns and wind patterns, which directly affects climate in those regions. (www.esrl.noaa.gov/gmd/grad/volcano.html)
A picture of Mount St. Helens in southern Washington, erupting in 1980.
Picture courtesy of: USGS/Courier-Journal
Perhaps the most notorious "climate changing" eruption occurred April 5-15, of 1815. These were the eruptions of Mount Tambora in Indonesia. These eruptions are theorized to have caused the "Year Without A Summer" in New England, the Canadian Maritimes, Newfoundland, and northern Europe the following year, 1816. Climate was affected so much in these locations that crops were very hard to grow and food shortages were common. This resulted in many deaths across the affected area during the summer of 1816. (USGS) For more information on the Mount Tambora eruption and "The Year Without A Summer" go to: (vulcan.wr.usgs.gov/Volcanoes/Indonesia/description_tambora_1815_eruption.html)
A satellite image of Mount St. Helens and the ash plume advecting southeast, just after eruption in 1980.
Picture courtesy of: NOAA
Ample amounts of volcanic ash in the atmosphere have been responsible for creating some magnificent sunsets. This picture was taken in Hong Kong, China after the 1992 eruption of Mount Pinatubo in the Philippines.
Picture courtesy of: Wikipedia
For more information on volcanic influences on sunsets go to: (www.spc.noaa.gov/publications/corfidi/sunset/)