New Perspectives by Considering Jointly Earth Gravity and Rotation <p> HR: <span class="hr"> 12:05h<br></span> AN: <span class="an"> G21E-07 INVITED <a href="../absbook/fm03-G21E.pdf">[PDF]</a><br></span> TI: <span class="ti"> New Perspectives by Considering Jointly Earth Gravity and Rotation <br></span> AU: <span class="au"> * Schuh, H <br></span> EM: <span class="em"> harald.schuh@tuwien.ac.at<br></span> AF: <span class="af"> Institute of Geodesy and Geophysics, Vienna University of Technology, Gusshausstr. 27-29, Wien, 1040 Austria <br></span> AU: <span class="au"> Fernandez, L <br></span> EM: <span class="em"> lauraf@fcaglp.unlp.edu.ar<br></span> AF: <span class="af"> Facultad de Ciencias Astronomicas y Geofisicas, Universidad La Plata, Paseo del Bosque, La Plata, B1900FWA Argentina <br></span> AB: <span class="ab"> The present satellite missions CHAMP and GRACE and the future GOCE satellite will allow to determine the gravity field of the Earth with high spatial and temporal resolution. A short overview about the present state of these missions will be given. As these satellites will play an important role for the new IAG lead project IGGOS (Integrated Global Geodetic Observing System) the relation between geometry and rotation of the Earth and it's gravity field will be described with respect to the interactions of the various components of system Earth. Mass redistribution, changes of the geometry and variations of the density are common causes for variations of Earth rotation and of the gravity field. Mass redistribution in surface fluid envelopes, e.g. in the oceans and in continental water reservoirs (soil moisture, snow cover, and groundwater), in the cryosphere, and to a small amount in the atmosphere could cause such variations that occur on very different time scales. As CHAMP and GRACE shall produce monthly gravity field solutions all short-term (hourly to weekly) atmospheric, oceanic and hydrological mass variations have to be taken into account because these mass variations cause time variant forces acting on the orbiting satellites. For this process, called de-aliasing, appropriate models of the mass variations are required that could be validated by observed short period EOP variations. Vice versa, medium and long periods detected in the gravity field could be taken for comparison and validation of EOP variations in the particular frequency band. The continental water storage change was studied using a model based on assimilated soil moisture and snow accumulation data from the NCEP/NCAR reanalysis with a Gaussian scheme grid of 1.875§ in longitude and about 1.905§ in latitude. The soil moisture data include two layers from the surface to 200 cm in depth. The Stokes time series were calculated up to degree two. Using the trace of the Earth inertia tensor as well as C20 changes, the variations of the EOP due to this continental hydrology model are shown. <br></span> DE: <span class="de"> 1200 GEODESY AND GRAVITY<br></span> DE: <span class="de"> 1223 Ocean/Earth/atmosphere interactions (3339)<br></span> DE: <span class="de"> 1239 Rotational variations<br></span> SC: <span class="sc"> Geodesy [G]<br></span> MN: <span class="mn"> 2003 Fall Meeting<br></span></p></body></html>