Two recently published reports propose different causes for the Chandler wobble excitation. One study suggests that earthquakes are important, while another investigation by us favors meteorological sources. Upon re-examination of the earthquake data, we find that the magnitude of the estimated earthquake contribution could explain about 25% of the Chandler wobble variance, but that there is no supporting evidence of correlation with observed polar motion. We conclude that there is presently no reason to believe the earthquake portion of the Chandler wobble excitation is any larger than 25%. On the other hand, the contribution of meteorological variation appears to be not less than 25%, and may easily be much more. |