11:15 AM - 11:30 AM
[G03-3-04] Evaluating strategies for mitigating aliasing errors in GRACE-like satellite missions
The aliasing of tidal and non-tidal geophysical signals with frequencies of less than one month into the monthly time-variable GRACE gravity field solutions is an often observed but only partially understood phenomenon. With increasing sensor accuracy (for example, GRACE-FO), the aliasing errors have been identified as the major stumbling blocks for the geophysical applications of satellite gravimetry data.
While aliasing affects all spherical harmonic coefficients, their impact on the higher harmonic degrees and orders can be reduced via parameter pre-elimination of low-degree sub-monthly (two-day) solutions often denoted as the Wiese-approach. In this study, we specifically look at how the Wiese-approach handles the aliasing errors, thereby analysing its mechanism in reducing aliasing errors. The Wiese-approach is implemented in the gravity field recovery process via the acceleration approach. In preceding studies, only the along-track acceleration has been used. Here, we demonstrate the benefit of the cross-track and the radial components of the acceleration vector in mitigating the aliasing errors. By using a noise-free simulation, we are able to specify upper bounds for the aliasing errors.
While aliasing affects all spherical harmonic coefficients, their impact on the higher harmonic degrees and orders can be reduced via parameter pre-elimination of low-degree sub-monthly (two-day) solutions often denoted as the Wiese-approach. In this study, we specifically look at how the Wiese-approach handles the aliasing errors, thereby analysing its mechanism in reducing aliasing errors. The Wiese-approach is implemented in the gravity field recovery process via the acceleration approach. In preceding studies, only the along-track acceleration has been used. Here, we demonstrate the benefit of the cross-track and the radial components of the acceleration vector in mitigating the aliasing errors. By using a noise-free simulation, we are able to specify upper bounds for the aliasing errors.