[LEAPSECS] This year's Y2K: 'Leap second' threatens to breakthe Internet -Brooks
brooks at edlmax.com
Thu Jan 15 09:45:52 EST 2015
New Research May Solve Puzzle in Sea Level's Rise
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).
> ----- Original Message -----
> From: "Tom Van Baak" <tvb at LeapSecond.com>
> To: "Leap Second Discussion List" <leapsecs at leapsecond.com>
> 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.
> 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"
> Or I can email you copies. I have the raw data here somewhere too.
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