New Research May Solve Puzzle in Sea Level's Rise
http://www.nytimes.com/2015/01/15/science/earth/new-research-may-solve-a-puzzle-in-sea-levels-rise.html
-Brooks
On 2015-01-15 06:57 AM, Tom Van Baak wrote:
Poul-Henning Kamp writes:
That reminds me, has anybody tried to do the math on climate change ?
The main effect is (probably?) going to be the thermal expansion of
the worlds oceans.
I did a quick back of the envelope calculation modeling the earth
as a sphere radius 6367 km, covered by a 4 km thick shell of water.
Increasing the thickness of the water by one meter but retaining
its mass, I get a realtive change in angular momentum of 6e-11 which
is in the order of a millisecond per year.
Below is a posting from last year; two plots are attached. It guesses long-term
climate LOD variations are on the order of 200 ms (that's leap second every
week territory).
/tvb
----- Original Message -----
From: "Tom Van Baak" <[email protected]>
To: "Leap Second Discussion List" <[email protected]>
Sent: Tuesday, April 15, 2014 7:32 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
_______________________________________________
LEAPSECS mailing list
[email protected]
https://pairlist6.pair.net/mailman/listinfo/leapsecs
_______________________________________________
LEAPSECS mailing list
[email protected]
https://pairlist6.pair.net/mailman/listinfo/leapsecs
