IGY Bulletin, Number 5, November 1957 - South pole winter weather review

Two nights ago I had a couple of peeks at the lunar eclipse. For once my insomnia had a benefit. The eclipse was notable for its reddish color and duration, the longest eclipse in over 1,000 years. If you didn't see it, this compilation of astro photos (with musical accompaniment, unfortunately) spanning the entire duration might satisfy you:

I was thinking that the mathematically beautiful predictability of such events is awesome, especially in these times that are uncertain in so many other ways.

Another characteristic of the Earth's orbit about the sun is how it generates seasons. Northern hemisphere winter actually occurs when the Earth is closest to the sun, so distance from the sun cannot be the cause of seasons. (My editor was surprised that orbits -- whether planetary or of satellites -- are elliptical, with a circular orbit being only a special case. This video explains with a modicum of qualitative physics why orbits are elliptical.) Furthermore, seasons are reversed in the northern and southern hemispheres. These facts can be explained by the fact that seasons are due to the tilt of the Earth's orbit. 

Reasons for the seasons (NASA)

So while we are getting lovely fall colors as shown in these recent neighborhood photos, it's now Spring in the southern hemisphere.

All this is a lead-in to the IGY Bulletin article on the South Pole winter weather review, from about June 20 - September 20, 1957. Most of this was within the official beginning portion of the IGY, which started on July 1, 1957. The article states that

A new [global] record low temperature of -102.1°F was measured at the Amundsen-Scott South Pole Station on September 17, 1957. This eclipses [no pun intended] the previous low of -100.4°F, which occurred on May 11 of this year.

The article continues that the previous record cold temperature of -90°F was set in Siberia in 1933. It also points out that the North pole is unlikely to see temperatures below -50°F because the Artic is an ocean covered with ice, as opposed to continental Antarctica. Water has a higher specific heat (i.e., temperatures respond to heat changes more sluggishly) than land, so temperature extremes on coasts and over an ocean are mitigated. In fact, the lowest temperature recorded in the northern hemisphere was not at the North Pole (in the midst of the Arctic Ocean) but over the landmass of Greenland, -93.3°F (-69.6 °C), on Dec. 22, 1991.

The lowest temperature since recorded at the Amundsen-Scott South Pole Station was -117.0°F (−82.8°C) on June 23, 1982.

The Bulletin article predicted that lower temperatures would likely be found further in the interior of Antarctica, nearer the Pole of Inaccessibility, which is further from the surrounding oceans than is the South Pole (see map in this previous post). The Soviet Union established a now-abandoned research station there later in the IGY. Wikipedia's page of weather records lists the now lowest recorded temperature of -128.6°F (-89.2°C) at another Russian Antarctic station, Vostok Station, on July 21, 1983. An even colder temperature of -136°F (-93.2°C) was inferred from remotely sensed measurements by satellites over the East Antarctic Plateau on Aug. 10, 2010.

The average winter temperature in 2021 at the Amundsen-Scott South Pole Station was -78°F (-61°C),  the coldest on record (even though there was not a new record for the single coldest day). Note that the graph below from an article in the Washington Post shows that the oldest data in this series dates to the IGY in 1957.

Average winter temperature at the South Pole since 1957 in °C (Richard Cullather/British Antarctic Survey)

Darn, all this is making me think of the approaching winter. Brrr.