Submitted by Anonymous on Sun, 11/13/2011 - 15:26
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Human Impacts in Antarctica 2011

Since the South Pole is so nearby, how accurate is a magnetic compass in Antarctica?

Linda

Wed, 11/16/2011 - 16:19

Michelle Brown

Hi Linda,The South Pole is more complicated than you might think. I was speaking
to Bob Melville (who I will be working with in mid-December at an AGO
site) and apparently there are 5 "South Poles":
1) The geographic South Pole -- This is the South Pole I will be
stopping in at. It is where all the latitude lines meet up. However,
since the Earth constantly wobbles while moving, it is not a permanent
marker and has to be re-aligned every year (I ate dinner with the guy
who realigns it every New Year's Day!).
2) Ceremonial South Pole -- This is where there is a marker at the
South Pole station base for photo ops. It is a custom to place a small
object on the marker, which has a metallic orb on top of it.
3) Instantaneous South Pole -- Remember I said that the Earth wobbles
so the South Pole is constantly changing? This means that there is an
instantaneous South Pole which is the accurate point where all the
longitudinal lines meet. It changes daily, but of course nobody measures
it every day.
4) Mean South Pole -- This is the average of all the instantaneous
South Poles.
5) Magnetic South Pole -- This is the point where the magnetic field is
being emitted from. Currently the magnetic south pole is in the ocean!
I know I didn't exactly answer your question--I'll have to work on that
one, but I thought I'd give you something to think about in the mean time!
Sincerely,
Michelle