Early one morning in late August 2019, Colorado photographer Glenn Randall hiked several miles to a stream flowing into Lake Isabelle in the Indian Peaks Wilderness. He set up his camera near the stream and began photographing about 20 minutes before sunrise when a golden glow developed at the horizon. It wasn’t until Randall was back at home, however, that he noticed something odd: The sky above the golden glow and its reflection in the water were both a deep violet.
He’s not alone. Photographers across the country have noticed that sunrises and sunsets have become unusually purple this summer and early fall.
Now, LASP researchers have collected new measurements that help to reveal the cause of those colorful displays: an eruption that occurred thousands of miles away on a Russian volcano called Raikoke.
The University of Colorado Boulder’s cross-campus Grand Challenge initiative this week announced the selection of three new additions to its portfolio starting this fall. The call for proposals, which was announced in June, funded one large research initiative at approximately $1 million per year and two smaller projects at $250,000 per year, each for at least three years. LASP will collaborate on the research initiative and on one of the two smaller projects.
The selections augment the current Grand Challenge portfolio, building on the accomplishments of Earth Lab, Integrated Remote and In Situ Sensing (IRISS), the university’s space minor, and the Center for the Study of Origins.
According to Cora Randall, CU professor and LASP research associate, the Aeronomy of Ice in the Mesosphere (AIM) Cloud Imaging and Particle Size (CIPS) instrument saw this season’s first polar mesospheric clouds on May 28. Polar mesospheric clouds, also called noctilucent or “night shining” clouds, form at about 50 miles above Earth’s surface and can be seen when they reflect light after sunset. The Northern Hemisphere cloud season generally begins in late May and lasts until late August; in the Southern Hemisphere, the season goes from late November to late February.