Assimilating GRACE/GRACE-FO Observations into JPL Terrestrial Reference Products
Claudio
Abbondanza
JPL/Caltech
Poster
Space gravimetry from GRACE/GRACE-FO (GGFO) provides quasi-monthly
estimates of mass redistribution that can be mapped to elastic surface
displacements. Although coarser in spatial resolution than point-wise
GNSS, GGFO-derived elastic displacements show strong consistency with
GNSS', particularly in the vertical component where correlations with IGS
Repro3 solutions reach ~0.7 for both CSR and JPL mascon products.
The spatial-scale complementarity between geometric and gravimetric
techniques has fostered the emerging field of hydrogeodesy, where joint
inversions exploit the point-wise nature of GNSS and the global-scale of GGFO
data to recover terrestrial water storage and other load-induced signals.
Beyond hydrological applications, terrestrial reference frame (TRF)
geodesy can also benefit from this synergy. At JPL, frame products are
generated with a square-root information Kalman filter in the spatial
domain -a formulation well suited to the assimilation of GGFO-inferred
surface deformation.
In standard realizations such as JTRF2020 and its update JTRF202-u2022,
non-tidal loading is represented by co-estimated seasonal
oscillators. As an alternative, GGFO-derived deformation can be
introduced directly as exogenous control inputs, driving the
load-responsive components of the TRF state without treating GGFO
data as observational constraints.
Here we report on the methodological developments and current status of
efforts to assimilate GRACE/GRACE-FO observations into JPL terrestrial
reference products, highlighting the potential to embed
space-gravimetry and geometric geodesy within a unified state-space
framework.
estimates of mass redistribution that can be mapped to elastic surface
displacements. Although coarser in spatial resolution than point-wise
GNSS, GGFO-derived elastic displacements show strong consistency with
GNSS', particularly in the vertical component where correlations with IGS
Repro3 solutions reach ~0.7 for both CSR and JPL mascon products.
The spatial-scale complementarity between geometric and gravimetric
techniques has fostered the emerging field of hydrogeodesy, where joint
inversions exploit the point-wise nature of GNSS and the global-scale of GGFO
data to recover terrestrial water storage and other load-induced signals.
Beyond hydrological applications, terrestrial reference frame (TRF)
geodesy can also benefit from this synergy. At JPL, frame products are
generated with a square-root information Kalman filter in the spatial
domain -a formulation well suited to the assimilation of GGFO-inferred
surface deformation.
In standard realizations such as JTRF2020 and its update JTRF202-u2022,
non-tidal loading is represented by co-estimated seasonal
oscillators. As an alternative, GGFO-derived deformation can be
introduced directly as exogenous control inputs, driving the
load-responsive components of the TRF state without treating GGFO
data as observational constraints.
Here we report on the methodological developments and current status of
efforts to assimilate GRACE/GRACE-FO observations into JPL terrestrial
reference products, highlighting the potential to embed
space-gravimetry and geometric geodesy within a unified state-space
framework.
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