The Analysis of the Observations of the Variation of Latitude

A statistical model of the variation of latitude is formulated and a detailed analysis of its properties is made. Difficulties arising from the necessity to account for observational errors are discussed. A computational procedure is obtained and applied to a 35-year series of observations in which the z-term has not been taken into account. It is found that the damping factor is $$k=0.322\pm0.103\,\text{year}^{-1}$$, giving a relaxation time of about 3.1 years; and the free period is $$2\pi /\gamma \,=\,1.267\pm\,0.039$$ years $$=462.8\pm\,14.2$$ mean solar days. The value of K is several times that of the only previous determination, and the free period is longer than has hitherto been determined. These results are provisional pending the completion of a full numerical analysis.