Is it a coincidence that we’re just past the end of the lowest sunspot cycle for over a century?
Dec. 28, 2020: Something strange is happening 50 miles above Antarctica. Or rather, not happening. Noctilucent clouds (NLCs), which normally blanket the frozen continent in December, are almost completely missing. These images from NASA’s AIM spacecraft compare Christmas Eve 2019 with Christmas Eve 2020:
“The comparison really is astounding,” says Cora Randall of the University of Colorado’s Laboratory for Atmospheric and Space Physics. “Noctilucent cloud frequencies are close to zero this year.”
NLCs are Earth’s highest clouds. They form when summertime wisps of water vapor rise up from the poles to the edge of space. Water crystallizing around specks of meteor dust 83 km (~50 miles) above Earth’s surface creates beautiful electric-blue structures, typically visible from November to February in the south, and May to August in the north.
A crucial point: Noctilucent clouds form during summer. And that’s the problem. Although summer officially started in Antarctica one week…
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via Tallbloke’s Talkshop
December 29, 2020 at 12:51PM