.
.
Unusual goings-on seen in the skies over New Zealand.

Dec. 4, 2019: An atmospheric wave nearly half as wide as Earth itself is supercharging noctilucent clouds (NLCs) in the southern hemisphere. NASA’s AIM spacecraft detected the phenomenon in this series of south polar images spanning Nov. 27th through Dec. 2nd:

“This is a clear sign of planetary wave activity,” says AIM principal investigator James Russell of Hampton University, which manages the Aeronomy of Ice in the Mesosphere mission for NASA.

Planetary waves are enormous ripples of temperature and pressure that form in Earth’s atmosphere in response to Coriolis forces. In this case, a 5-day planetary wave is boosting noctilucent clouds over Antarctica and causing them to spin outward to latitudes where NLCs are rarely seen.

On Dec. 1st, Mirko Harnisch saw the clouds from Dunedin, New Zealand. “I was enjoying the late-evening sky over the Southern Ocean just after 11 pm local time when these wispy blue-ish clouds appeared,”…