I remember driving out to southeastern Washington for my first summer of combine driving in early June, 1974. We were camping in snow drifts in Yellowstone National Park on the way. I note that the SOI Index for '74 was very high. Big La Nina year. It was not that high again until 2010. My Biology companion was finding the season's first edible mushrooms along the melt-patch edges of the drifts.
Yes, interesting weather. We got soaked last night and may get more. But the canoe is not floating yet.
Copied from the Space Weather newsletter. RECORD COLD IN THE MESOSPHERE: It's getting cold in the mesosphere. Very cold. "At polar latitudes (60N-80N) temperatures have been breaking 14-year records in the last few days," says Lynn Harvey of the University of Colorado Laboratory for Atmospheric and Space Physics. This development is causing noctilucent clouds (NLCs) to spill out of the Arctic to middle latitudes.
"I've been waiting for years to see NLCs, and finally it happened!" reports Phil Halpert from London, England, on June 7th. He noticed their electric-blue ripples over local rooftops, then rushed out to photograph them in open sky over Clissold Park:
"This is the first time I have ever seen noctilucent clouds over London!" he says.
NLCs are Earth's highest clouds. Seeded by meteoroids, they float at the edge of space 83 km above the ground. The clouds form when summertime wisps of water vapor rise up to the mesosphere, allowing water to crystallize around specks of meteor smoke. Usually they are best seen after the summer solstice, but this year they are getting an early start.
What's happening? To find out, Harvey has been looking at data from NASA's Microwave Limb Sounder (MLS), which can sense conditions 83 km high where NLCs form. "These plots show that 2020 is shaping up to be a very cold and wet year," she says.
"Temperatures, in particular, are very cold," she says. "In fact, mid-latitude (35N-55N) temperatures in late May (DOY 142-148) were the coldest of the AIM record"--that is, since 2007 when NASA's AIM spacecraft began monitoring noctilucent clouds.
Last summer, NLCs spread as far south as Los Angeles and Las Vegas, setting records for low-latitude sightings. The growing chill today suggests this summer could be just as good--or maybe even better. In fact, the first sightings in the continental USA (Washington and Minnesota) have already happened.
Observing tips: The best time to look for NLCs is during the hours after sunset (or before sunrise) when the sun is more than 6 degrees below the horizon: diagram. If you see electric-blue tendrils spreading across the sky, take a picture and submit it here.
I'm totally out of my league here, Mr. Birder. What is the practical effect of "coldest on record" Mesosphere temperatures? Other than lower latitude noctilucent clouds, of course.
Could these clouds reduce (reflect) photons headed for the earth?
An interesting thought - we only call them Noctilucent because that is when we can see them - they are there all the time. So they must have some effect on the albedo in some frequencies.
This satellite photo reminds me of water freezing on a windscreen
"Noctilucent clouds, also known as polar mesospheric clouds, form in a part of the atmosphere roughly 50 to 86 kilometers (30 to 54 miles) above the surface of our planet. In the months following AIM’s early observations, researchers working with the satellite shared some of their findings. They discovered that the clouds appear daily, are widespread, and vary on an hourly to daily basis. They also found that the clouds’ brightness varies over horizontal scales of about 3 kilometers (2 miles). To their surprise, the researchers also noticed that the ice in the mesosphere—the layer of the atmosphere where the clouds form—occurs in a single, continuous layer stretching from about 82 to 89 kilometers (51 to 55 miles) above the Earth’s surface."