Zimbabwe continues to have vivid sunsets caused by aerosols from the 22 April eruption of Calbuco volcano. This evening’s display included dynamic kaleidoscopic patterns of color from shifting crepuscular rays and moving reflections of sunlight from both diffuse static patches of aerosols high in the sky and a thin broken layer of low atmospheric cloud moving in from the west.
The most spectacular portion was captured in a time-lapse sequence of 28 photographs taken at about 20-second intervals, which have been combined to produce the accompanying animated gif.
The camera used was a tripod mounted Panasonic Lumix DMC-TZ 60 in sunset auto mode with wide angle lens.
Dario Almonacid posted the following video of Calbuco volcano to YouTube on the day of the eruption.
Les Cowley explains volcanic sunsets at his website Atmospheric Optics:
Volcanic eruptions can inject millions of tons of dust and gaseous sulfur dioxide into the stratosphere. The finer dust particles remain aloft for years and spread around the world while the sulphur dioxide evolves to an aerosol of sulfur acids that add to the particulates.
The dust and aerosol produce vivid sunset and twilight effects like the intense yellow-red horizon and purple-pink glows of the photograph. The purple glow is probably a combination of red-orange light transmitted through the lower atmosphere and scattered blue light from still sunlit stratospheric dust.
The volcanic ash has another optical effect. The small particles can diffract light to form a huge variant of a corona called a Bishop’s ring.
Post published in: Environment