Noctilucent cloud season over the Arctic began May 27th 2018

Space Weather
Thu, 31 May 2018 16:17 UTC

© Catalin Tapardel

August 5, 2017 @ Kakwa, Alberta, Canada

NASA's Aeronomy of Ice in the Mesosphere (AIM) spacecraft has spotted its first noctilucent clouds (NLCs) of the 2018 season. They are the electric-blue puffs circled in this image of the Arctic taken by AIM's CIPS instrument on May 27th:

"The summer season for noctilucent clouds has begun," says Cora Randall, AIM science team member at the University of Colorado. "We spotted the first hint of NLCs in our data on May 23rd; now they are brightening rapidly."

NLCs are Earth's highest clouds. Seeded by meteoroids, they float at the edge of space more than 80 km above the planet's surface. The clouds form when summertime wisps of water vapor waft up and crystallize around specks of meteor smoke.

Previous data from AIM have shown that NLCs are like a great "geophysical light bulb." They turn on every year in late spring, reaching almost full intensity over a period of 5 to 10 days. This means observers on the ground could begin to see them not long after AIM does.

Early-season NLCs are usually faint and always found in high latitude places such as Canada, the British isles, Siberia and Scandinavia. To people in those areas, we offer the following observing tips: Look west 30+ minutes after sunset when the sun has dipped 6^o or more below the horizon. If you see luminous blue-white tendrils spreading across the sky, you may have spotted a noctilucent cloud.

Comment: Interestingly, it's the 31st of May, but June 15th 2017 Space Weather reported in The mystery of absent noctilucent clouds:

During the first two weeks of June 2017, Spaceweather.com received zero images of NLCs - something that hasn't happened in nearly 20 years.

Where did they go? Researchers have just figured it out: There's been a "heat wave" in the polar mesosphere, a region in Earth's upper atmosphere where NLCs form. Relatively warm temperatures have wiped out the clouds.

So with the unsettling rise in fireballs, one would think the two would increase in tandem, and yet, evidently, our atmosphere isn't behaving as is expected. And perhaps when this year's peak occurs will provide more data on just what's going on up there:

• Adapt 2030 Ice Age Report: Arctic atmosphere changed, noctilucent clouds and Hawaii eruption hits geothermal well
• Noctilucent rocket fumes filmed over Okinawa Island, Japan
• Rare green flash sunset photographed flickering into even rarer blue in Norway
• Last year's solar eclipse set off a wave in the upper atmosphere that was detected as far away as Brazil
• Cosmic rays increased 12% this year plus an awesome 'diamond dust' sun halo sighted in Montana (PHOTOS)