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Panoramic photograph showing volcanic twilight at sunset from Lubbock on 4 September. Click on the image for a larger view. Photo by Todd Lindley – National Weather Service, Lubbock. |
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Volcanic Sunrises and Sunsets
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The late part of August and early part of September 2008 brought unusually colored sunrises and sunsets over the South Plains.
In fact, astute sky observers across much of the U.S. and Europe photographed vivid colors and rays at sunrise and sunset during the end of August and the first half of September. These displays were highlighted by dramatic rayed features and brilliant colors that range from yellow and orange, to fiery red, and a rarely seen glowing purple.
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Animated graphic displaying how the sulfur dioxide from the eruption of Mount Kasatochi was distributed across the northern hemisphere by upper level winds. The brighter colors are higher concentrations of sulfur dioxide. |
Meteorologists blame this phenomenon on a series of volcanic eruptions in Alaska’s Aleutian Islands, namely the 7 August eruption of Mount Kasatochi. The Alaskan eruptions ejected tons of sulfur dioxide, dust, and ash into the upper portions of the atmosphere, and a thin undulating layer of upper atmospheric dust and aerosols was even visible during many of the displays. This material in the Earth’s stratosphere scatters sunlight as the sun slips below the horizon. Lower level clouds frequently cast shadows upon the layer of dust and gas to result in vivid twilight rays projected skyward from the horizon.
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Volcanic aerosols visible in cloudless skies within minutes of sunset (left) and a brilliant volcanic twilight at sunrise on 4 September. Click on the pictures for a larger view. Photos by Todd Lindley – National Weather Service, Lubbock. |
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The first reports of unusual sunset phenomenon were received from the U.S. Pacific Northwest on 17 August. In the weeks after the Kasatochi’s eruption, winds some 35,000 to 45,000 feet above the ground dispersed the volcanic material over most of the northern hemisphere within global circulations, and resulted in an intensification of twilight from North America to Asia. These colorful displays, known as “volcanic twilight”, historically occur around the globe following major volcanic eruptions. It is not uncommon for decades to pass before such effects are observed again.
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Photos taken during volcanic sunsets from Floyd County on 24 August. Click on the images for a larger view. Photos by the Texas Tech University West Texas Mesonet. |
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A meteorologist at the Texas Tech University West Texas Mesonet, photographed one of the first such volcanic sunsets visible from west Texas in the skies above Floyd County on Sunday, 24 August (above). Unusual twilights continued to be observed from Lubbock through early September. However, by mid-September the volcanic twilight displays have subsided.
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Panoramic photograph showing volcanic twilight at sunset from Lubbock on 3 September. Click on the image for a larger view. Photo by Todd Lindley - National Weather Service, Lubbock. |
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Although these displays varied from day-to-day until diminishing by mid-September, they did bring many memorable volcanic sunrises and sunsets! Similar sunrises and sunsets were last seen over our region following the June 1991 eruption of Mount Pinatubo in the Philippines. |