Re: [LEAPSECS] Introduction of long term scheduling

From: Steve Allen <sla_at_UCOLICK.ORG>
Date: Mon, 1 Jan 2007 11:56:26 -0800

On Mon 2007-01-01T19:29:19 +0000, Poul-Henning Kamp hath writ:
> >McCarthy pretty much answered this question in 2001 as I reiterate here
> >
> What exactly is the Y axis on this graph ?

Only McCarthy can say for sure.
Maybe someone elsewho was at the GSIC meeting could give a better idea.

My impression is that McCarthy generated a pseudorandom sequence of
LOD values based on the known power spectrum of the LOD fluctutations
and then applied the current UT1 prediction filters to that to see
how wrong UT1-UTC was likely to get. I suspect it was a rather
back of the envelope kind of calculation that was not repeated
because the notions of scheduling that it posited were shot down.

As a routine matter of operation the IERS would undoubtedly want
to put some effort into verifying that new software for making such
predictions was well reviewed and tested.

Oh, and the lawyer in me just asserted a loophole in my previous post.

One could say that it was never possible for the BIH/IERS to guarantee
that its leap second scheduling could meet the 0.7 s and then later
0.9 s specification because they could not be held responsible for
things that the earth might do. As such the IERS could conceivably
start unilaterally issuing full decade scheduling of leap seconds and
claim that it *was* acting in strict conformance with ITU-R TF.460.

In civil matters this is the sort of action which would later be
tested in court if it were found to have adverse effects. In the
matter of earth rotation it seems unlikely that there could be any
penalties, and if there were a general consensus that this be the
right thing to do then the IERS could probably act with impunity in
advance of official approval from all agencies.

Steve Allen                 <>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99858
University of California    Voice: +1 831 459 3046           Lng -122.06014
Santa Cruz, CA 95064     Hgt +250 m
Received on Mon Jan 01 2007 - 11:56:49 PST

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