On Wed 2007-01-17T12:31:14 -0700, Warner Losh hath writ:
> It has been remarked that the current state of the art is that 100ms
> accuracy can be predicted about a year in advance only and that the
> models are constantly undergoing refinement. It has been estimated
> that IERS could issue leap seconds, with today's technology, about 3-5
> years out and still be in a 95% or 99% band of certainty that the 0.9s
> margin is maintained. However, I can't find papers that show these
> models or point to any better data than hearsay...
The best that I know of were the ones presented at the Colloquium that
the WP7A SRG held in Torino in May 2003. There was a time when the
host institution (IEN) was providing the proceedings online, but the
contents of that URL went away sometime around a year ago. (I wonder
if they may not have liked the conclusion that was reached.)
In the spirit of promulgation I provide what they once did at
http://www.ucolick.org/~sla/leapsecs/torino/ITU.shtml
The conclusion was originally a powerpoint drafted in real time, it is
http://www.ucolick.org/~sla/leapsecs/torino/closure.pdf
The indications of how well predictions of UT1 might be done are found
in three presentations to which Felicitas Arias contributed.
There are two which were powerpoint
http://www.ucolick.org/~sla/leapsecs/torino/guinot.pdf
http://www.ucolick.org/~sla/leapsecs/torino/arias_2.pdf
and one which is a more verbose writeup of one of the powerpoints
http://www.ucolick.org/~sla/leapsecs/torino/arias_3.pdf
The plots by Arias indicate how well UT1 could have been predicted
over two and three year intervals for the 40 year interval starting
around 1960. It is based on those plots that I have voiced no
concerns for the pointing of our telescopes if leap seconds were
published five years in advance. I'm not ready to go for ten.
--
Steve Allen <sla_at_ucolick.org> 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 http://www.ucolick.org/~sla/ Hgt +250 m
Received on Wed Jan 17 2007 - 23:12:11 PST