A Brief Light to Get By

Current Conditions
Temperature: -24F
Wind Chill: -50F

Another two day weekend gone. Only one left in August and then the return of fresh legs in early September. The station's population will double for a month during "Winfly," the extra bodies working in preparation for the summer season. In early October the summer hoards will begin their return. My departure is tentatively set for October 25th. By that time the station will be full up with 1000 energetic people again and I'm not looking forward to it, having settled into the mellow and involuntary sleepiness of winter.

Along with recent clear skies come the frigid temperatures normally associated with this time of year. The clear skies also bring views of the heavens, auroras, and even signs that the sun is returning toward the horizon. I took these pictures last weekend at mid-day:

This is the first we've seen of polar nacreous clouds, which are associated with the ozone hole. They are common in the springtime here, and are said to be responsible for some of the best scenery of the polar year. I look forward to seeing more. You can see Orion's belt and scabbard in upper left of this one:

And this one I just took today:

Auroras have been common the past few weeks, but not spectacular. I've seen them on many occasions, usually in the afternoon while I'm driving to various scientific sites. They've been low in the sky and gentle green with movement at a snail's pace, nothing like the brightly dancing display I saw near Fairbanks in September.

Part of the reason the auroras are mild is that we are not in a prime location for viewing them. The charged particles coming in from space are funneled by the earth's magnetic field toward the poles, the magnetic poles, that is, which are slightly off center from the geographic poles (actually, McMurdo is closer to the magnetic south pole than the geographic South Pole is). Due to the way the magnetic flux lines work, these particles interact with the atmosphere at a given radius from the magnetic pole, as shown in this auroral prediction image:
At the thick green band, the auroras will be directly overhead. Because McMurdo is some distance west of the band, the auroras generally appear fairly low on our eastern horizon. That's not to say that we don't get auroras directly overhead, we do, just not very often.

The other reason the auroras are not particularly spectacular is that we are at the low point in the solar cycle, a repeating 11 year period of solar activity. Less activity, less aurora. In 5 years the cycle will be at its peak again. Maybe I'll come back then! This is a pretty typical view of the auroras I've seen:

There have been a few occasions that the light show was directly above and filled much of the sky. It's still amazing to watch, but I keep hoping for something to rival my previous experience.