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 > >http://www.ucolick.org/~sla/leapsecs/McCarthy.html > > 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 <[EMAIL PROTECTED]> 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