ALE informed me of an interesting tidbit. Apparently one of the weird things about Antarctica is the barometric pressure is quite low. This causes altimeters relying on barometric pressure to work poorly.
That means that my GPS with an altimeter and my sports watch will not function as well as I’d like. Although, elevation is not that critical for this particular trek. All I need to know is I’ll be traveling between 5000 and 9000 feet. Latitude is far more useful for navigation than anything else.
Plus, the weather is hugely variable down there, meaning the barometric pressure will be changing all the time. That translates into no real practical way for me to calibrate the altimeters.
The relative barometric pressure is interesting, however, as it tells me what the weather is probably going to turn to. So, that will still be a useful measure.
Just not for elevation.