The secular trend of the rotation pole had been a source of controversies since the first astronomical evidence of secular change in the latitude of the observatories as far back
as 1872 (Markowitz, 1960). Table here below report the empirical values achived for several authors using modern determination, i.e. since the including of space geodetic data sets (see
Dickman, 2000 for a review).
| Researchers |
time span |
trend rate |
trend direction |
| (mas/year) |
(° to the W longitude) |
| Wilson and Vicente (1980) |
1900-1977 |
3.4 |
66 |
| Dickman (1981) |
1900-1979 |
3.52 |
80.1 |
| Gross (1982) |
1899-1979 |
3.96 |
69.3
|
| Chao (1983) |
1900-1979
|
3.52
|
79.4
|
| Okamoto and Kikuchi (1983) |
1899-1979
|
3.46
|
80.6
|
| Poma et al. (1991) |
1900-1979
|
3.4 |
79 |
| Vondrak et al. (1995) |
1900-1990 |
3.31 |
78.1 |
MacCarthy and Luzum (1996)
ILS+BIH+NEOS
NEOS |
1899-1994
1976-1994
|
3.33
3.39
|
75
85.4
|
Gross (1998)
ILS Space96
HIPPARCOS |
1900-1979
1976-1997
1899-199 |
3.8
4.123
3.51 |
75.5
73.9
79.2 |
| Vondrak (1999) |
1899-1998
|
3.294
|
75.7
|
| Schuh et al. (2001) |
1899-1992
|
3.31
|
76.08
|
We also provide pole coordinates averaged over decadal time by applying Gaussian filter.
See the mean pole and
its tabulated values x ("), y(") at 0.05 year interval since 1900.
References:
- Chao, B. F. (1983)Autorregresive Harmonic Analysis of the Earth's polar motion using Homogeneous International Latitude Service data. J. Geophys. Res. 88, pp. 10299-10307.
- Dickman, S.R. (1981) Investigation of controvertial polar motion features using homogeneous ILS data. J. Geophys. Res. 86, pp.4904-4912.
- Dickman, S.R. (2000)Tectonic and Cryospheric excitation of the Chandler Wooble and a Brief review of the secular motion of the Earth's rotation pole. IAU Colloquium 178: Polar Motion Historical and Scientific Problems . ASP Conference series, Vol. 208. pp. 411-435.
- Gross, R.S. (1982)A determination an Analysis of polar motion.Ph.D. dissert.; University of Colorado.
- Gross, R.S. (1998)EOS Fall Meeting
- MacCarthy, D. D.; Luzum B. J. (1996) Path of the mean rotational pole from 1899 to 1994. Geophys. J. International, 125, pp. 623-629.
- Okamoto, I. and Kikuchi, N. (1983) Public. Int. Latit. Obs. Mizusawa, 16, pp. 35-?
- Poma, A.; Proverbio, E. and Uras S. (1991), Public. Staz. Astron. Carloforte - Cagliari, 14, pp. 19 -?
- Schuh, H.; Nagel, S.; Seitz T. (2001) Linear drift and periodoc variations observed in long time series of polar motion.Journal of Geodesy, 74;pp. 701-710.
- Vondrak, J.; Ron, C.; Pesek, I. and Cepek A. (1995) New Global Solution of Earth orientation parameters from optical astrometry in 1900-1990. Astron. Astrophys., 297, pp. 899-906
- Vondrak, J. (1999)Secular and long-periodic polar motion as derived from combination of astrometric and space geodetic observations.Journées 1998 Système Référence Spatio-Temporels, N. Capitaine ed. Observ. Paris, pp. 195-201.
- Wilson, C. and Vicente, R. (1980) An analysis of the homogeneous ILS polarmotion series. Geophys. J. R. astr. Soc., 62, pp. 605-616.