Fig. 3

Latitude variation data in 1899–1901. The residual of the latitude variation at Mizusawa (a) and another one of the latitude observatories at Carloforte, Italy, (b) before (top) and after (bottom) introducing the new longitude-independent annual term (Z-term). Red curves in a, b indicate the monthly values of the new term. The polar motion during the first year of ILS is shown in c. Re-drawn using the latitude variation residuals, the values of the Z-term, and the polar motion data in Kimura (1902b)