Re: [LEAPSECS] The real problem with leap seconds

From: Michael Deckers <Michael.Deckers_at_FUJITSU-SIEMENS.COM>
Date: Wed, 18 Jan 2006 10:13:10 +0000

   On 2006-01-18, Steve Allen wrote:

> Now I am confused.
>
> By my reading of the documents, ITU-R did not define DTAI until the
> most recent revision of TF.460 in 2002. DUT1 had been defined since
> very early on.

   You are right, the name DTAI has apparently been introduced in 2002. It
   also appears in [ITU-R TF536.2 2003] and [ITU-R TF686.2 2002]. It is
   defined in these documents as the values of TAI - UTC and is described
   as the contribution of the IERS to the determination of UTC. Such values
   of TAI - UTC are published back to 1972 (step function) and even to 1961
   (piecewise linear function).

   Since I wanted to describe how I understood Mark Calabretta's
   description of UTC as essentially the same as TAI except for the
   variable radix notation for the (whole) second field in the time
   of day values, I took DTAI as a convenient abbreviation of
            TAI - ( UTC value when interpreted with
                    a fixed radix for the second field )
   I avoided writing UTC for TAI - DTAI because this would contradict
   the assumption that UTC is just TAI plus additional information.
   Hope that clarifies things a bit.

   Michael Deckers
Received on Wed Jan 18 2006 - 02:13:34 PST