SECULAR POLAR MOTION

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: