Intraseasonal variability in atmospheric surface pressure and relationship to polar motion

Two techniques were used to validate the theoretical relationship between polar motion and P sub s variations. The first method, reproduced from Hide et al. (1984), compares the fluctuations in physical space of the polar spirals and the high frequencies about them. Although the agreement appears reasonable, the lack of a clear measure of closeness and the presence of the large Chandler signal itself makes a comparison at higher frequencies difficult. To overcome this difficulty, the authors present the X functions required to maintain the observed fluctuations at roughly 20 to 70 days and those calculated from the National Meteorological Center (NMC) P sub s data. These curves are in relatively good agreement, indicating that polar motions are indeed driven, at least in large part, by fluctuations in P sub s.