Temporal Gravity Variations in GOCE Gradiometric Data

Jarecki, F.; Müller, Jürgen; Schwintzer, P.

doi:10.1007/3-540-26932-0_58

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…More detailed simulation studies have confirmed that temporal gravity field variations generally remain far below the GOCE noise level (Jarecki et al 2005;Han et al 2006;Moore and King 2010). The extended mission duration now foreseen will hardly change this situation.…”

Section: Goce Versus Gracementioning

confidence: 93%

GOCE, Satellite Gravimetry and Antarctic Mass Transports

Rummel

Horwath

et al. 2011

Surv Geophys

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In 2009 the European Space Agency satellite mission GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) was launched. Its objectives are the precise and detailed determination of the Earth's gravity field and geoid. Its core instrument, a three axis gravitational gradiometer, measures the gravity gradient components V xx , V yy , V zz and V xz (second-order derivatives of the gravity potential V) with high precision and V xy , V yz with low precision, all in the instrument reference frame. The long wavelength gravity field is recovered from the orbit, measured by GPS (Global Positioning System). Characteristic elements of the mission are precise star tracking, a Sun-synchronous and very low (260 km) orbit, angular control by magnetic torquing and an extremely stiff and thermally stable instrument environment. GOCE is complementary to GRACE (Gravity Recovery and Climate Experiment), another satellite gravity mission, launched in 2002. While GRACE is designed to measure temporal gravity variations, albeit with limited spatial resolution, GOCE is aiming at maximum spatial resolution, at the expense of accuracy at large spatial scales. Thus, GOCE will not provide temporal variations but is tailored to the recovery of the fine scales of the stationary field. GRACE is very successful in delivering time series of large-scale mass changes of the Antarctic ice sheet, among other things. Currently, emphasis of respective GRACE analyses is on regional refinement and on changes of temporal trends. One of the challenges is the separation of ice mass changes from glacial isostatic adjustment. Already from a few months of GOCE data, detailed gravity gradients can be recovered. They are presented here for the area of Antarctica. As one application, GOCE gravity gradients are an important addition to the sparse gravity data of Antarctica. They will help studies of the crustal and lithospheric field. A second area of application is ocean circulation. The geoid surface from the gravity field model GOCO01S allows us now to generate rather detailed maps of the mean dynamic ocean topography and of geostrophic flow velocities in the region of the Antarctic Circumpolar Current.

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Section: Goce Versus Gracementioning

confidence: 93%

GOCE, Satellite Gravimetry and Antarctic Mass Transports

Rummel

Horwath

et al. 2011

Surv Geophys

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“…For example Han et al (2004), Jarecki et al (2005) and Han et al (2006) sphere, oceans and hydrology in terms of the geoid and gravity gradients. These studies have shown GOCE to be insensitive to ocean tides and other mass redistributions at the seasonal scale.…”

Section: Introductionmentioning

confidence: 99%

Satellite gravity gradiometry: Secular gravity field change over polar regions

Moore¹,

King²

2010

Journal of Geodynamics

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a b s t r a c tThe ESA Gravity and steady state Ocean and Circulation Explorer, GOCE, mission will utilise the principle of satellite gravity gradiometry to measure the long to medium wavelengths in the static gravity field. Previous studies have demonstrated the low sensitivity of GOCE to ocean tides and to temporal gravity field variations at the seasonal scale. In this study we investigate the sensitivity of satellite gradiometry missions such as GOCE to secular signals due to ice-mass change observed in Greenland and Antarctica. We show that unaccounted ice-mass change signal is likely to increase GOCE-related noise but that the expected present-day polar ice-mass change is below the GOCE sensitivity for an 18-month mission. Furthermore, 2-3 orders of magnitude improvement in the gradiometry in future gradiometer missions is necessary to detect ice-mass change with sufficient accuracy at the spatial resolution of interest.

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Temporal Gravity Variations in GOCE Gradiometric Data

Jarecki

Müller

Schwintzer

International Association of Geodesy Symposia

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Abstract. The accuracy and spatial resolution expected from GOCE gravity gradiometry might deteriorate due to temporal gravity variations, which are mainly induced by mass redistributions in the System Earth. These mass redistributions occur in the atmosphere at various time scales, in the oceans as ocean tides and currents and on the continents as solid Earth tides, loading and hydrological effects. Opposite to GRACE, GOCE is developed to measure the static gravity field. Therefore, any time variable effects have to be removed from the measured data prior to further processing in a dealiasing step. In this report the effects mentioned above are analysed by means of available models in order to investigate if they deliver significant contributions to the GOCE gradiometer measurements. Simulations of the different system parts (Atmosphere, Hydrosphere, Cryosphere and Solid Earth) are run. The gravitational effect of the simulated mass changes is expanded into spherical harmonics from which gravitational gradients are computed along a simulated GOCE orbit. The resulting gradients are compared with the specifications of the GOCE gradiometer. Furthermore, the residual (i.e. atmospheric and oceanic parts removed) time variable part of the gravity field as detected by GRACE is discussed with respect to its impact on GOCE gradiometry.

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Temporal Gravity Variations in GOCE Gradiometric Data

Cited by 5 publications

References 9 publications

GOCE, Satellite Gravimetry and Antarctic Mass Transports

GOCE, Satellite Gravimetry and Antarctic Mass Transports

Satellite gravity gradiometry: Secular gravity field change over polar regions

Temporal Gravity Variations in GOCE Gradiometric Data

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