Contributions to Proceedings:
M. Schindelegger, J. Böhm, D. Salstein:
"Analysis of atmosphere-excited intraseasonal polar motion via the torque approach";
in: "Proceedings of the Journées 2013 "Systémes de Référence Spatio-Temporels",
issued by: Nicole Capitaine;
Proceedings by N. Capitaine,
Alongside the diagnosis of changes in fluid angular momentum, geophysically-driven perturbations of Earth rotation can be investigated by means of interaction torques arising at the boundary of the solid Earth. A recently published reassessment of this modeling route demonstrates the success of investigating torque quantities for the specific purpose of accounting for atmosphere-induced polar motion at intraseasonal periodicities. Here, we expand those considerations by a more detailed analysis of the well-known 10-day atmospheric normal mode signal in polar motion in terms of the underlying driving mechanisms provided by mountain, friction, and equatorial bulge torques. If a fully isostatic response of the sea surface to air pressure variations is implemented, mountain and bulge torque are shown to elicit wobbling motion in the 10-day band at roughly the same level, with the underlying local contributions being dominant over northern hemispheric landmasses. In combination with consistently calculated oceanic angular momentum estimates, atmospheric interaction torques provide a well-closed equatorial excitation budget across the frequency range of 1 to 2 weeks.
Electronic version of the publication:
Created from the Publication Database of the Vienna University of Technology.