[LEAPSECS] LEAPSECS Digest, Vol 153, Issue 3

[Tom Van Baak]

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" <tvb at LeapSecond.com>
To: "Leap Second Discussion List" <leapsecs at leapsecond.com>
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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