Tuesday, July 11, 2023

Noctilucent clouds in relation to solar maximum

NLC seen at my QTH in 2019

This is a kind of opposite post to the one I wrote in 2019 . This ES season brings us noticable less good propagation to Japan and USA till now. Somehow generally they think that NLC and PMSE certainly have something to do with propagation at high latitudes. But the way this mechanism works is not really known.

This year there are almost no NLC visible. Due to the active sun that is hitting Earth's upper atmosphere with lots of extreme ultraviolet radiation. These high energy photons make it harder for ice crystals to form in the mesosphere, thus suppressing NLCs.

Luckely it is not the only form of propagation. We are almost in the solar maximum and F2 propagation is expected on 50MHz later this year. We'll see what it brings us. 

More to read:

https://spaceweather.com/archive.php?view=1&day=02&month=07&year=2023

https://pe4bas.blogspot.com/2017/07/nlcs-pmse-and-sssp.html

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