CoAuthors

Neumayer Karl-Hans (GFZ German Research Centre for Geosciences, Germany); Dettmering Denise (Deutsches Geodaetisches Forschungsinstitut der Technischen Universitaet Muenchen (DGFI-TUM), Germany); Esselborn Saskia (GFZ German Research Centre for Geosciences, Germany); Schöne Tilo (GFZ German Research Centre for Geosciences, Germany)

Precise orbits of altimetry satellites are a prerequisite for investigations of global and regional mean sea level changes. Using the recent versions of the orbit solutions of altimetry satellites Jason-1, Jason-2, TOPEX/Poseidon, Envisat, ERS-1 and ERS-2 derived at GFZ in the frame of the ESA Sea Level Climate Change Initiative and DFG UHR-GravDat projects we show improvements in the orbit quality, as provided by the orbital analysis, altimetry single-satellite crossover analysis and the multi-mission crossover analysis. These improvements are due to using new time variable Earth gravity field models, improved satellite attitude and macromodels, new tropospheric correction models for DORIS observations, improvements in the solar radiation pressure modeling. Thus, the internal consistency in the radial direction of the latest (VER11) orbit solutions derived at GFZ is 1.8 cm for ERS-1 and ERS-2, 1.0 cm for TOPEX/Poseidon, 0.4 cm for Envisat, 0.8 cm for Jason-1 and Jason-2. However, there are still some deficiencies in the quality of the latest orbit solutions, providing a room for further improvements by using new realizations of the Terrestrial Reference Frame, new models of the Earth gravity field models, improved modeling of non-gravitational forces acting on altimetry satellites and other improvements.