[time-nuts] UTC and leap seconds

Magnus Danielson magnus at rubidium.dyndns.org
Sat Jun 12 11:45:11 UTC 2010


On 06/12/2010 02:33 AM, Hal Murray wrote:
>
> jimlux at earthlink.net said:
>> The Chilean earthquake changed the angular rotation rate (or, probably  more
>> accurately, changed the direction of the axis of rotation as well)
>> of the earth a small amount, as do most large earthquakes.
>
> Has anybody measured that?
>
> Is there a good URL on this?  (predictions if not data)  All I've found so
> far is a small NASA press release predicting 1.26 microseconds per day:
>    http://www.nasa.gov/topics/earth/features/earth-20100301.html
> (and a zillion news sources repeating it)
>
> 1 microsecond/day is 1 part in 1E11.

There is one place that keeps track of these things, the IERS. Their 
Bullentin B provides monthly reports of earth rotation observatoins.

The bulletin for relevant period of time is:
ftp://hpiers.obspm.fr/iers/bul/bulb_new/bulletinb.266
ftp://hpiers.obspm.fr/iers/bul/bulb_new/bulletinb.267

Explanations is in:
ftp://hpiers.obspm.fr/iers/bul/bulb_new/bulletinb.pdf

Clause 3 is of most interest, look at the OMEGA column (appended the 
bulletin b 267 data for a more complete time-series around the date of 
interest).

3 - EARTH ANGULAR VELOCITY : DAILY FINAL VALUES OF LOD, OMEGA AT 0hUTC

  LOD     : Excess of the Length of day - 86400 s TAI
  OMEGA   : Earth angular velocity
  Description: ftp://hpiers.obspm.fr/iers/bul/bulb_new/bulletinb.pdf

     DATE        MJD     LOD     sigma      OMEGA           sigma
  (0 h UTC)              ms       ms        mas/ms          mas/ms

2010   2   2   55229  1.8681  0.0026  15.04106685346    0.00000000045
2010   2   3   55230  1.7864  0.0026  15.04106686768    0.00000000045
2010   2   4   55231  1.5385  0.0025  15.04106691084    0.00000000044
2010   2   5   55232  1.2685  0.0025  15.04106695784    0.00000000044
2010   2   6   55233  1.0554  0.0025  15.04106699494    0.00000000044
2010   2   7   55234  0.8434  0.0025  15.04106703185    0.00000000044
2010   2   8   55235  0.6803  0.0024  15.04106706024    0.00000000042
2010   2   9   55236  0.5753  0.0023  15.04106707852    0.00000000040
2010   2  10   55237  0.5670  0.0024  15.04106707996    0.00000000042
2010   2  11   55238  0.6693  0.0025  15.04106706215    0.00000000044
2010   2  12   55239  0.8218  0.0025  15.04106703561    0.00000000044
2010   2  13   55240  0.9954  0.0025  15.04106700538    0.00000000044
2010   2  14   55241  1.1595  0.0023  15.04106697682    0.00000000040
2010   2  15   55242  1.3130  0.0022  15.04106695009    0.00000000038
2010   2  16   55243  1.4267  0.0022  15.04106693030    0.00000000038
2010   2  17   55244  1.4902  0.0022  15.04106691925    0.00000000038
2010   2  18   55245  1.4938  0.0022  15.04106691862    0.00000000038
2010   2  19   55246  1.4125  0.0022  15.04106693277    0.00000000038
2010   2  20   55247  1.2918  0.0022  15.04106695379    0.00000000038
2010   2  21   55248  1.1747  0.0023  15.04106697417    0.00000000040
2010   2  22   55249  1.0692  0.0024  15.04106699254    0.00000000042
2010   2  23   55250  0.9790  0.0023  15.04106700824    0.00000000040
2010   2  24   55251  0.9995  0.0023  15.04106700467    0.00000000040
2010   2  25   55252  1.1888  0.0023  15.04106697172    0.00000000040
2010   2  26   55253  1.4628  0.0023  15.04106692402    0.00000000040
2010   2  27   55254  1.7307  0.0023  15.04106687738    0.00000000040
2010   2  28   55255  1.9743  0.0024  15.04106683497    0.00000000042
2010   3   1   55256  2.0942  0.0024  15.04106681410    0.00000000042
2010   3   2   55257  2.0008  0.0023  15.04106683036    0.00000000040
2010   3   3   55258  1.7548  0.0022  15.04106687318    0.00000000038
2010   3   4   55259  1.4776  0.0023  15.04106692144    0.00000000040
2010   3   5   55260  1.2055  0.0022  15.04106696881    0.00000000038
2010   3   6   55261  0.9666  0.0022  15.04106701040    0.00000000038
2010   3   7   55262  0.8211  0.0022  15.04106703573    0.00000000038
2010   3   8   55263  0.7631  0.0022  15.04106704582    0.00000000038
2010   3   9   55264  0.8364  0.0022  15.04106703306    0.00000000038
2010   3  10   55265  0.9253  0.0022  15.04106701759    0.00000000038
2010   3  11   55266  0.9827  0.0023  15.04106700760    0.00000000040
2010   3  12   55267  1.0913  0.0022  15.04106698869    0.00000000038
2010   3  13   55268  1.1363  0.0022  15.04106698086    0.00000000038
2010   3  14   55269  1.1201  0.0021  15.04106698368    0.00000000037
2010   3  15   55270  1.1643  0.0020  15.04106697598    0.00000000035
2010   3  16   55271  1.2107  0.0021  15.04106696790    0.00000000037
2010   3  17   55272  1.2396  0.0021  15.04106696287    0.00000000037
2010   3  18   55273  1.1762  0.0020  15.04106697391    0.00000000035
2010   3  19   55274  0.9807  0.0020  15.04106700794    0.00000000035
2010   3  20   55275  0.8169  0.0020  15.04106703646    0.00000000035
2010   3  21   55276  0.6733  0.0019  15.04106706146    0.00000000033
2010   3  22   55277  0.5584  0.0019  15.04106708146    0.00000000033
2010   3  23   55278  0.5350  0.0019  15.04106708553    0.00000000033
2010   3  24   55279  0.6588  0.0018  15.04106706398    0.00000000031
2010   3  25   55280  0.9540  0.0018  15.04106701259    0.00000000031
2010   3  26   55281  1.3046  0.0019  15.04106695156    0.00000000033
2010   3  27   55282  1.6142  0.0019  15.04106689766    0.00000000033
2010   3  28   55283  1.8512  0.0018  15.04106685640    0.00000000031
2010   3  29   55284  1.9790  0.0018  15.04106683415    0.00000000031
2010   3  30   55285  1.9111  0.0019  15.04106684597    0.00000000033
2010   3  31   55286  1.6414  0.0019  15.04106689292    0.00000000033
2010   4   1   55287  1.3068  0.0018  15.04106695117    0.00000000031

Yes, we see a dip there... but looking at the two-month data we se a 
regular pattern creating a dip there... and the lack of jump is interesting.

Essentially... I can't see it here.

Cheers,
Magnus



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