Everest 3.7 metres shorter than in 1975: China

Everest 3.7 metres shorter than in 1975: China

October 18, 2005

THE TRUE HEIGHT OF MOUNT EVEREST LINGERS

A recent survey by a Chinese scientific team produced a new height for
Mount Everest.

Read press release at:

        http://in.rediff.com/news/2005/oct/09china.htm

Still a propaganda excercise,

Jan

(and 'significant digits' is not their strongest point)
And note that all that GPS stuff is rather irrelevant.
The main uncertainty is in the geoid height,
about 8800 metres lower.

J. J. Lodder wrote...

Crass overstating of insignificant digits was my initial reaction but it
turns out to be stupid typo by the reporter - according to a more reputable
site what was actually said by the Chinese DG of Surveying was that the
latest height was 8844.43m with a margin of error of about 0.21m, which is
much more reasonable.

I don't think that there is any significant difference between this and the
previous measurement. The difference in this case is that they were able to
measure the thickness of ice on top of the summit (3.5m) whereas previously
the depth was estimated by penetrating with a steel rod and assuming that
they had hit rock at 0.9m. Kang Shichang, of the Chinese Academy of
Sciences, said that the latest results were proof that the Chinese survey in
1975 had underestimated the thickness of the ice.

This isn't the first time that GPS has been used to estimate the height of
the mountain - a couple of Americans used a Trimble instrument in May 1999
and came up with a height of 8850m, but I've no idea whether any attempt was
made to correct for the thickness of the ice-cap.

The other interesting comment was the mention of 50 surveying experts in the
Chinese team. In reality the expedition had two purposes - surveying the
height of the mountain and cleaning it up as part of the preparations for
hosting the 2008 Olympics - so that the majority of the mountaineers were
actually expert rubbish collectors!

David

snip

In principle GPS by itself
is useless to give you the true height of any mountain.
It only tells you where the summit is,
in relation to the centre of the earth.
What you need top know in addition is the geoid height below it.
And no GPS can find that.


There have been clean-up excerises on the other side too.
They removed not only lots of empty cans,
but even a body of a climber left by his comrades.

The authorities there should make a law
saying that you must bring down everything you carry up.
With heavy fines for violators of course.

Best,

Jan

Tell that to the Boston Museum of Science and National Geographic...they
went to a lot of effort to get accurate results.


Lots of bodies up there that will never be recovered; not a problem. The
old oxygen bottles bring big bucks from collectors so they were all
recovered long ago. New bottles are never left behind.


They have been in place for years on both sides. The whole "trash
problem" has always been greatly overblown. The reall issues are from
base camp down but nobody likes to talk about that.