Effects of Earth tides on LAGEOS and LAGEOS II satellites and their influence on the detection of the Lense-Thirring effect

An extensive analysis of the perturbations induced on node and perigee of LAGEOS and LAGEOS II by solid and ocean Earth tides is carried out in order to assess their influence in the detection of the secular general relativistic Lense-Thirring effect by means of these two satellites. The investigation involves only the terms of degree l = 2 for the solid tides and also the terms of degree l = 3 and l = 4 for the ocean tides. The perigee of LAGEOS II results to be very sensitive to these terms, contrary to the nodes of LAGEOS and LAGEOS II. The uncertainty on the solid tidal perturbations, mainly due to the Love number k2, amounts almost to 0.3 %, while the errors associated to the ocean tides are of the order of 10− 15 %. The results obtained are employed in reducing the experimental uncertainty on the Lense-Thirring precession due to the zonal tides by means of a suitable combination of orbital residuals. The 18.6-year tide affects the value of the Lense-Thirring effect derivable from such an observable at a level of 21.9 % of its general relativistic value. iorio: effects of earth tides on lageos and lageos ii satellites... 1