Abstract The accuracy of the conservative force-models is not clear and the new space accelerometers provide a unique opportunity for their validation. In this paper, the conservative-force model deficiencies are investigated via Principal Component Analysis (PCA) using 4 years of GRACE measurements (2006–2009). The deficiencies are assessed by comparing the accelerometer readouts with the differences between the conservative force-model and the precise orbit accelerations. Within this scheme, the spatiotemporal data analysis is synthesized in a time-series of grids whose latitudinal and longitudinal variations are respectively influenced by the half orbital period and the equatorial orbit shift. With maximum amplitude of 50 nm/s2, the mean map shows a positive overestimation in Canada and Brazil and negative in Greenland. Explaining the 74% of the variability, the two first pairs of PCA modes show un-modeled patterns with amplitudes maxima of 80 nm/s2 and 50 nm/s2. Their periodic behavior and wave-length of degree-6 and degree-11s spherical harmonics strongly suggest an additional modeling and improvement. As for the long-term variations, our results show a latitudinal variation of 15 nm/s2 maximum amplitude correlated with the day-night periods. Performing a combined analysis of ascending and descending orbits, a trend of 3 nm/s2yr in the Indian Ocean is also observed. Our new approach for orbital force-models validation can be considered crucial for the current state-of-the-art of precise orbit determination (POD) and Time–Varying Gravity (TVG) modeling.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Assessment of conservative force models from GRACE accelerometers and precise orbit determination


    Contributors:

    Published in:

    Publication date :

    2015-11-29


    Size :

    8 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English





    Precise Orbit Determination for GRACE

    Kang, Z. / Nagel, P. / Pastor, R. et al. | British Library Conference Proceedings | 2003


    Precise orbit determination for GRACE

    Kang, Z / Nagel, P / Pastor, R | Elsevier | 2003


    Precise orbit determination for GRACE

    Kang, Z. | Online Contents | 2003


    GRACE Precise Orbit Determination (AAS 03-253)

    Kang, Z. / Tapley, B. / Bettadpur, S. et al. | British Library Conference Proceedings | 2003