On 7/15/2020 10:42 AM, Demetrios Matsakis via LEAPSECS wrote:
> There is a well-known decrease in the slow-down due to the global
> warming since the ice ages. Basically the ice caps melt, the oceans
> rise, and the Earth gets rounder. But the same people who do that
> math say today’s warming, dramatic as it may be for our biosphere, is
> too little for this particular effect. People have gotten that
> stuff wrong since George Darwin, though.
Attached are 380k year plots of sea level (lod-msl-fig1.gif) and
estimated LOD (lod-msl-fig7.gif).
The two papers of interest are cached here:
http://leapsecond.com/pages/lod/2010-Chapanov-Gambis-Long-Variations-Earth-Rotation.pdf
*Long-Periodical Variations of Earth Rotation, Determined from
Reconstructed Millennial-Scale Glacial Sea Level*
Yavor Chapanov, Daniel Gambis
http://leapsecond.com/pages/lod/2003-Sidall-Glacial_Sea_Lvl_Red_Sea-Na03.pdf
*Sea-level fluctuations during the last glacial cycle**
*M. Siddall, E. J. Rohling, A. Almogi-Labin, Ch. Hemleben, D. Meischner,
I. Schmelzer, D. A. Smeed
See below for the thread from 2014.
https://pairlist6.pair.net/pipermail/leapsecs/2014-April/005112.html
/tvb
----- Original Message -----
From: "Tom Van Baak" <[email protected]>
To: "Leap Second Discussion List" <[email protected]>
Sent: Tuesday, April 15, 2014 8:32 AM
Subject: Re: [LEAPSECS] Earth speeding up?
> I'm not a geophysicist, but I too have noted what Tom reports. I've
attached
> a plot that by coincidence I just made last week.
>
> 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.
> Short-term fluctuations are much better understood, and they
correlate very strongly
> with the atmospheric angular momentum.
>
> Demetrios,
Thanks for sharing that one. Now, do you dare join the club and predict
the year when we hit 86400.000?
For a longer-term view, attached are two plots from a 2010 paper
"Long-Periodical Variations of Earth Rotation, Determined from
Reconstructed Millennial-Scale Glacial Sea Level" by Chapanov & Gambis
translating mean sea level to excess LOD.
See also the 2003 Nature paper "Sea-level fluctuations during the last
glacial cycle" by Siddall & Rohling.
One of these papers is from "New challenges for reference systems and
numerical standards in astronomy"
http://syrte.obspm.fr/jsr/journees2010/pdf/
Or I can email you copies. I have the raw data here somewhere too.
/tvb
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