Changes in accuracy of gravity recovery due to ground track variability: GRACE, CHAMP, and GOCE Changes in accuracy of gravity recovery due to ground track variability: GRACE, CHAMP, and GOCE <p> HR: <span class="hr"> 1340h<br></span> AN: <span class="an"> G33A-0897 <a href="../absbook/fm07_G33A.html">[Abstracts]</a><br></span> TI: <span class="ti"> Changes in accuracy of gravity recovery due to ground track variability: GRACE, CHAMP, and GOCE Changes in accuracy of gravity recovery due to ground track variability: GRACE, CHAMP, and GOCE<br></span> AU: <span class="au"> * Klokocnik, J<br></span> EM: <span class="em"> jklokocn@asu.cas.cz<br></span> AF: <span class="af"> Astronom. Inst. Czech Acad. Sci., CZ 251 65 Ondrejov observatory Czech Republic, Ondrejov, 251 65, Czech Republic <br></span> AU: <span class="au"> Wagner, C A<br></span> EM: <span class="em"> Carl.Wagner@noaa.gov<br></span> AF: <span class="af"> NOAA, Lab. Satel. Altimetry, Silver Spring, MD, Silver Spring, 20910-3226, United States <br></span> AU: <span class="au"> McAdoo, D<br></span> EM: <span class="em"> Dave.McAdoo@noaa.gov<br></span> AF: <span class="af"> NOAA, Lab. Satel. Altimetry, Silver Spring, MD, Silver Spring, 20910-3226, United States <br></span> AU: <span class="au"> Kostelecky, J<br></span> EM: <span class="em"> kost@fsv.cvut.cz<br></span> AF: <span class="af"> Research Inst. of Geodesy, CZ 250 66 Zdiby 98, Zdiby, 250 66, Czech Republic <br></span> AU: <span class="au"> Bezdek, A<br></span> EM: <span class="em"> bezdek@asu.cas.cz<br></span> AF: <span class="af"> Astronom. Inst. Czech Acad. Sci., CZ 251 65 Ondrejov observatory Czech Republic, Ondrejov, 251 65, Czech Republic <br></span> AU: <span class="au"> Novak, P<br></span> EM: <span class="em"> Pavel.Novak@pecny.cz<br></span> AF: <span class="af"> Dept. Math. Fac. Applied Sci., West Bohemian Univ., Universitni 6, Plzen, Plzen, 300 80, Czech Republic <br></span> AU: <span class="au"> Gruber, C<br></span> EM: <span class="em"> gruber@asu.cas.cz<br></span> AF: <span class="af"> Astronom. Inst. Czech Acad. Sci., CZ 251 65 Ondrejov observatory Czech Republic, Ondrejov, 251 65, Czech Republic <br></span> AB: <span class="ab"> Following an earlier recognition of degraded monthly geopotential recovery from GRACE (Gravity Recovery And Climate Experiment) due to prolonged passage through a short repeat (low order resonant) orbit, we extend these insights to the whole of this and other current and future continuous tracking missions, in particular to CHAMP (CHAllenging Minisatellite Payload) and GOCE (Gravity field and steady state Ocean Circulation Explorer). The extension from geopotential results for exact repeat missions to the general case for non-repeat free-falling orbits is made through the proxy of the satellite ground track density, in particular its maximum spacing in longitude over a given period of time. We illustrate wide track-density variations over time for these orbits in both latitude and longitude and estimate geopotential recovery will be as widely affected as well within these regimes; lesser density of the tracks leading to poorer recoveries. We have used recent models of atmospheric density to estimate minimum and maximum drag and the orbit decrease of GRACE and provide a warning of future degraded performance as other low order resonances are encountered. We have also found the variations of the densities of the ground tracks of CHAMP correlate well with quality of geopotential parameters derived from this satellite. Finally, implications for the GOCE orbit are also discussed, with some suggestions for its orbit in the scheduled measuring phases of this mission, to avoid low-order resonances. <br></span> DE: <span class="de"> 1214 Geopotential theory and determination (0903)<br></span> DE: <span class="de"> 1217 Time variable gravity (7223, 7230)<br></span> DE: <span class="de"> 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)<br></span> SC: <span class="sc"> Geodesy [G]<br></span> MN: <span class="mn"> 2007 Fall Meeting<br></span></p></body></html>