Excitation of Chandler Wobble by Pacific, Indian and Atlantic Oceans from 1980 to 2005

In addition to the atmosphere, the oceans play important roles in the excitation of the Chandler wobble. The contributions made by the Pacific Ocean, the Indian Ocean and the Atlantic Ocean from 1980 to 2005 to the excitation of the Chandler wobble are first and systematically researched by taking advantage of the data of the current velocity field and ocean floor pressure provided by the marine circulation model of the Estimating the Circulation and Climate of the Ocean (ECCO). Studies show that the contributions of the three oceans to the excitation of the Chandler wobble are different from one another: the excitation energy of the Pacific Ocean makes up about 22.2% of the observational excitation energy, the largest one among the three oceans, that of the Indian Ocean accounts for about 12.7% and that of the Atlantic Ocean amounts to about 7.1%, the smallest among the three great oceans. The remarkable increase in the excitation energy of the Chandler wobble by the Pacific Ocean may be possibly due to the effect of the strong ENSO event which occurred from 1982 to 1983.