[LEAPSECS] Earth speeding up?

[Matsakis, Demetrios]

Indeed, Greenland is a textbook case of "glacial rebound".   As its ice cap has been melting away, the land mass has been noticeably rising.

-----Original Message-----
From: Poul-Henning Kamp [mailto:phk at phk.freebsd.dk] 
Sent: Tuesday, April 15, 2014 11:41 AM
To: Leap Second Discussion List; Matsakis, Demetrios
Subject: Re: [LEAPSECS] Earth speeding up?

In message <E517A9AF6A49AA479D731EC5F891C0BBFE81D1DF at echo.usno.navy.mil>, "Mats akis, Demetrios" writes:


>The best hand-waiving arguments I've heard for these recent "decadal 

>fluctuations" is that the oblateness of the Earth is changing, possibly 

>due to the ice caps changing.


Well, I'd somewhat doubt that.

The Arctic is sea-ice, so no net change in gravity or weight there.

Antartica ?   Probably not.  Our measurements of ice volume would
have to be spectacularly wrong, in which case we will soon have other and much more pressing problems than leap seconds.

But Greenland might be relevant, it's close to the pole, significantly assymetrical, and loosing a lot of mass (far too) quickly.

But again, I have a hard time coming up with a purely geometrical effect, given what we know about the ice volume in play.

A more likely explanation would an effect on the mantel-core interface under Greenland, which would make it anybodys guess what will happen.

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