[LEAPSECS] Crunching Bulletin B numbers

Mark Calabretta mcalabre at atnf.csiro.au
Tue Feb 15 19:39:31 EST 2011

On Tue 2011/02/15 15:25:49 PDT, Rob Seaman wrote
in a message to: Leap Second Discussion List <leapsecs at leapsecond.com>

>Correct me if I'm wrong: Bulletin A are the predictions (using methods

>presumably less advanced than the EOP PCC). Bulletin B are the final

>observed parameters.

Yes, but the explanatory supplement for Bulletin B recommends using
EOP C01 (1846-present given in the IERS 1997 system) for scientific
analysis. In fact, the EOP PCC was based on EOP C04 (1962-present
in IAU2000A).

>My point is that whatever the necessary input data (including such

>things as atmospheric angular momentum models), the new-and-improved

>predictions can be compared against the archival data. The data

>challenge (at least for this purpose) doesn't have to be conducted

>in real time.

Every week, the EOP PCC participants used EOP 05 C04 data to predict
EOP for the next 10, 30, and 500 days using a variety of methods,
mostly purely mathematical, though some used predictions of
atmospheric and oceanographic angular momentum (presumably for short-
term predictions only). Predictions had to be submitted before EOP
measurements for that week became available, and they were later
compared to the measurements.

It would be circular then to compare the predictions against EOP C04

Mark Calabretta

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