5:30 PM - 5:45 PM
[G03-1-04] Constellations of Next Generation Gravity Missions: mapping and mitigation of ocean tide model errors
The GRACE and GOCE satellite missions have shown the great potential of using space-borne gravimetry for observing mass transport in the system Earth. However, for meeting future user needs, it is crucial to enhance both the spatial and temporal resolution. This can be achieved by a Bender-type Next Generation Gravity Mission (NGGM) that consists of a constellation of two GRACE-type satellite tandems, with one pair flying in a (near-)polar orbit and the other in an inclined orbit. In addition, GRACE-type satellites will be implemented with improved sensor packages, including laser-based low-low satellite-to-satellite tracking (ll-SST) instruments, more precise accelerometers and state-of-the-art star trackers.
The European Space Agency (ESA) study “ADDCON" (ADDitional CONstellations) aims at investigating the impact of several orbit design choices on the performance of temporal gravity field retrieval by Bender-type NGGMs. Simulation studies have indicated that for such constellations aliasing of errors in ocean tide models is a dominant error source in retrieved temporal gravity field. As part of the ADDCON study, ocean tide model errors are mapped first in terms of ll-SST range-rate residuals for several Bender-type NGGMs, with orbits varying in altitude, repeat period and inclination (prograde and retrograde). This provides among others insight in the geographical distribution of ll-SST observation residuals due to errors in ocean tide models. Second, the ocean tide model errors are mapped to gravity field errors in terms of spherical harmonic (SH) expansions for retrievals ranging from one day to a month and for maximum SH degrees ranging from 10 to 120. Third and finally, the possibility of mitigating the impact of ocean tide model error on gravity field retrieval by tuning the set of estimated parameters has been explored (including estimation of empirical accelerations, so-called Wiese approach, etc.).
The European Space Agency (ESA) study “ADDCON" (ADDitional CONstellations) aims at investigating the impact of several orbit design choices on the performance of temporal gravity field retrieval by Bender-type NGGMs. Simulation studies have indicated that for such constellations aliasing of errors in ocean tide models is a dominant error source in retrieved temporal gravity field. As part of the ADDCON study, ocean tide model errors are mapped first in terms of ll-SST range-rate residuals for several Bender-type NGGMs, with orbits varying in altitude, repeat period and inclination (prograde and retrograde). This provides among others insight in the geographical distribution of ll-SST observation residuals due to errors in ocean tide models. Second, the ocean tide model errors are mapped to gravity field errors in terms of spherical harmonic (SH) expansions for retrievals ranging from one day to a month and for maximum SH degrees ranging from 10 to 120. Third and finally, the possibility of mitigating the impact of ocean tide model error on gravity field retrieval by tuning the set of estimated parameters has been explored (including estimation of empirical accelerations, so-called Wiese approach, etc.).