Effect of the stratified ocean of the core upon the Chandler wobble

it is supposed that a stably stratified layer exists at the top of the fluid core: we call it the stratified ocean of the core (SOC). Thr assumed model of the SOC has a sharp density drop at the boundary with the bulk of the core, and a uniform internal density gradient. The influence of the SOC upon the Chandler wobble is considered. It is shown that the action of Archimedean buoyancy forces in the SOC creates inside this layer an additional fluid velocity of order of (C-H/2 sigma)v(tau). Here C-H is the relative density deficit in the SOC, upsilon(tau) is the velocity associated with the Chandler wobble without the SOC, and sigma similar to 1/400 is the frequency of the Chandler wobble measured in cycles per day The effect of the SOC on the Chandler wobble is small: it increases the wobble period by similar to 0.1 day, and its contribution to the dissipation of the wobble energy is about six orders of magnitude smaller than the observed dissipation. A change of seismic velocity in the SOC due to the greater concentration of the light admixture is discussed. A comparison of the conditions in the SOC with the conditions at the inner core boundary shows that the extra amount of the light fluid in the layer increases the seismic velocity; therefore, the SOC is a high-velocity layer. (C) 2000 Elsevier Science B.V. All rights reserved.