Precise estimation of in situ geopotential differences from GRACE low‐low satellite‐to‐satellite tracking and accelerometer data

Han, Shin‐Chan; Shum, C. K.; Jekeli, Christopher

doi:10.1029/2005jb003719

Cited by 35 publications

(33 citation statements)

References 15 publications

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“…These KBR Rate (KBRR) residuals represent the gravitational effects of non-modelled phenomena, and mainly the contribution of continental hydrology. They are easily converted into variations of along-track potential differences between the two GRACE satellites, following the energy integral method as proposed earlier by Jekeli (1999), Han et al (2006) and lately Ramillien et al (2011). Once corrected from known gravitational accelerations, along-track Residual Differences of Potential (RDP) mainly caused by hydrology variations in a selected continental region can reach ±0.1 m 2 /s 2 within a precision of ∼10 −3 m 2 /s 2 (see Ramillien et al 2011).…”

Section: Grace-based Residual Potential Differences To Be Invertedmentioning

confidence: 99%

Sequential estimation of surface water mass changes from daily satellite gravimetry data

Ramillien

Frappart

Gratton

et al. 2014

J Geod

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We propose a recursive Kalman filtering approach to map regional spatio-temporal variations of terrestrial water mass over large continental areas, such as South America. Instead of correcting hydrology model outputs by the GRACE observations using a Kalman filter estimation strategy, regional 2-by-2 degree water mass solutions are constructed by integration of daily potential differences deduced from GRACE K-band range rate (KBRR) measurements. Recovery of regional water mass anomaly averages obtained by accumulation of information of daily noise-free simulated GRACE data shows that convergence is relatively fast and yields accurate solutions. In the case of cumulating real GRACE KBRR data contaminated by observational noise, the sequential method of step-by-step integration provides estimates of water mass variation for the period 2004-2011 by considering a set of suitable a priori error uncertainty parameters to stabilize the inversion. Spatial and temporal averages of the Kalman filter solutions over river basin surfaces are consistent with the ones computed using global monthly/10-day GRACE solutions from official providers CSR, GFZ and JPL. They are also highly correlated to in situ records of river discharges (70-95 %), especially for the Obidos station where the total outflow of the Amazon River is measured. The sparse daily coverage of the GRACE satellite tracks limits the time resolution of the regional Kalman filter solutions, and thus the detection of short-term hydrological events.

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Section: Grace-based Residual Potential Differences To Be Invertedmentioning

confidence: 99%

Sequential estimation of surface water mass changes from daily satellite gravimetry data

Ramillien

Frappart

Gratton

et al. 2014

J Geod

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“…We used KBRR to determine the geopotential differences. The theories used in GEOGRACE are based largely on the works of Jekeli (1999) and Han et al (2006). A new least-squares parameter estimation technique and a new accelerometer calibration technique are presented in this paper and in GEOGRACE, along with other features.…”

Section: Along-track Geopotential Differencementioning

confidence: 99%

“…(15). Following the recommendations of Kim (2000) and Han et al (2006), for very satellite revolution p 1 and p 2 were estimated once, while p 3 -p 6 were estimated twice. The targeted geopotential difference was obtained as…”

Section: Calibrating Accelerometer Datamentioning

confidence: 99%

“…This opens an opportunity for improving the gravity solution in both theoretical and practical aspects. GEOGRACE was developed based on Han et al (2006) and Tangdamrongsub et al (2012) with a state-of-art modification. Extending from Tangdamrongsub et al (2012), a numerical method and a clear procedure to estimate satellite-to-satellite geopotential differences and its formal error at the GRACE satellite altitude using the public GRACE L1B (Level-1B) product (Case et al 2010) is described.…”

Section: Introductionmentioning

confidence: 99%

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Along-Track Geopotential Difference and Deflection of the Vertical from GRACE Range Rate: Use of GEOGRACE

Tangdamrongsub

Hwang²

2016

Terr. Atmos. Ocean. Sci.

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We present a theory and numerical algorithm to directly determine the time-varying along-track geopotential difference and deflection of the vertical at the Gravity Recovery and Climate Experiment (GRACE) satellite altitude. The determination was implemented using the GEOGRACE computer program using the K-band range rate (KBRR) of GRACE from the Level-1B (L1B) product. The method treated KBRR, GPS-derived orbit of GRACE and an initial geopotential difference as measurements used in the least-squares estimation of the geopotential difference and its formal error constrained by the energy conservation principle. The computational procedure consisted of three steps: data reading and interpolation, data calibration and estimations of the geopotential difference and its error. The formal error allowed removal of KBRR outliers that contaminated the gravity solutions. We used the most recent models to account for the gravity changes from multiple sources. A case study was carried out over India to estimate surface mass anomalies from GEOGRACE-derived geopotential differences. The 10-day mass changes were consistent with those from the MASCON solutions of NASA (correlation coefficient up to 0.88). Using the geopotential difference at satellite altitude avoids the errors caused by downward continuation, enabling the detection of small-scale mass changes.

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“…As explained by Han et al (2006) in detail, the potential difference V 1,2 (t) can be computed by combining the inter-satellite range-rate, the position, velocity and acceleration data of the two GRACE satellites again through the energy balance approach. The observation equation for a single observation…”

Section: Spatio-temporal Grace-only Modelmentioning

confidence: 99%

Regional gravity modeling in terms of spherical base functions

Schmidt¹,

Fengler

Mayer‐Gürr

et al. 2006

J Geod

Self Cite

134

106

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This article provides a survey on modern methods of regional gravity field modeling on the sphere. Starting with the classical theory of spherical harmonics, we outline the transition towards space-localizing methods such as spherical splines and wavelets. Special emphasis is given to the relations among these methods, which all involve radial base functions. Moreover, we provide extensive applications of these methods and numerical results from real space-borne data of recent satellite gravity missions, namely the Challenging Minisatellite Payload (CHAMP) and the Gravity Recovery and Climate Experiment (GRACE). We also derive high-resolution gravity field models by effectively combining space-borne and surface measurements using a new weighted level-combination concept. In addition, we outline and apply a strategy for constructing spatiotemporal fields from regional data sets spanning different observation periods.

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Precise estimation of in situ geopotential differences from GRACE low‐low satellite‐to‐satellite tracking and accelerometer data

Cited by 35 publications

References 15 publications

Sequential estimation of surface water mass changes from daily satellite gravimetry data

Sequential estimation of surface water mass changes from daily satellite gravimetry data

Along-Track Geopotential Difference and Deflection of the Vertical from GRACE Range Rate: Use of GEOGRACE

Regional gravity modeling in terms of spherical base functions

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