摘要： ► Kinematic orbits of COSMIC satellites and GRACE satellites are determined to cm accuracy using GPS. ► Dynamic orbits (with a static gravity field) of the 8 satellites are determined using GEODYN II. ► Monthly gravity harmonic coefficients to degree 5 are determined from orbit perturbations. ► GPS-derived zonal coefficients are consistent with the SLR and GRACE KBR results. This paper demonstrates estimation of time-varying gravity harmonic coefficients from GPS data of COSMIC and GRACE satellite missions. The kinematic orbits of COSMIC and GRACE are determined to the cm-level accuracy. The NASA Goddard's GEODYN II software is used to model the orbit dynamics of COSMIC and GRACE, including the effect of a static gravity field. The surface forces are estimated per one orbital period. Residual orbits generated from kinematic and reference orbits serve as observables to determine the harmonic coefficients in the weighted-constraint least-squares. The monthly COSMIC and GRACE GPS data from September 2006 to December 2007 (16 months) are processed to estimate harmonic coefficients to degree 5. The geoid variations from the GPS and CSR RL04 (GRACE) solutions show consistent patterns over space and time, especially in regions of active hydrological changes. The monthly GPS-derived second zonal coefficient closely resembles the SLR-derived and CSR RL04 values, and third and fourth zonal coefficients resemble the CSR RL04 values. 出版者： Elsevier Ltd 出版日期： 2012 出處： Journal of geodynamics, 2012, Vol.53, p.34-42 資源來源： ScienceDirect (Elsevier) Journals 版權： 2011 Elsevier Ltd 識別號： ISSN: 0264-3707 識別號： ISSN: 1879-1670 識別號： DOI: 10.1016/j.jog.2011.08.004
