Sunday, August 31, 2014
Aurora season begins, NLC season ends
Source - Space Weather News for Aug. 31, 2014: http://spaceweather.com
Aurora season is now fully underway around the Arctic circle. With the end of northern summer approaching, dancing green lights are beaming through the deepening polar twilight on a regular basis. Unlike lower latitudes, the Arctic does not require a full-fledged geomagnetic storm for aurora sightings.
Check the latest images on the front page of http://spaceweather.com
Meanwhile, another polar phenomenon is on the wane: noctilucent clouds (NLCs). Data from NASA's AIM spacecraft suggest that the northern summer season for NLCs ended on or about August 26th. The "noctilucent daisy" shown on http://spaceweather.com will probably remain blank until November, when NLC activity shifts to the southern hemisphere. NLCs are a summertime phenomenon and they switch back and forth between the hemispheres accordingly. Stay tuned for more electric blue ... in a few months.