Regional contributions to the atmospheric excitation of rapid polar motions

Daily fields of surface pressure produced by the National Meteorological Center during 1981-1985 are used to identify the sectors of the globe over which changes in atmospheric mass contribute most importantly to the excitation of intraseasonal variations in the earth's polar axis. Maxima in the excitation function are found over the extratropical South Pacific, North Pacific, and North Atlantic, consistent with previous studies that have identified maxima in surface pressure variations in these regions. Because these centers are located over the ocean, the manner in which the ocean responds to changes in the atmospheric mass above it becomes of central importance in fully understanding the causes of rapid polar motions.