A review of the GGP network and scientific challenges

Crossley, David; Hinderer, J.

doi:10.1016/j.jog.2009.09.019

Cited by 26 publications

(16 citation statements)

References 20 publications

(21 reference statements)

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“…At the Geodetic Observatory Wettzell, the change of gravitational acceleration (referred to hereafter as gravity changes) are measured continuously by the SG 029, which is part of the Global Geodynamics Project (GGP) network [ Crossley and Hinderer , 2009; Crossley et al , 1999]. Vertical gravity changes are recorded by the SG based on the current of the feedback coil required to levitate the superconducting sphere in a persistent magnetic field [ Goodkind , 1999].…”

Section: Study Area and Datamentioning

confidence: 99%

Total water storage dynamics in response to climate variability and extremes: Inference from long‐term terrestrial gravity measurement

et al. 2012

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[1] Terrestrial water storage is a basic element of the hydrological cycle and a key state variable for land surface-atmosphere interaction. However, measuring water storage in a comprehensive way for different storage compartments and beyond the point scale is a challenge. In this study, we explore a 10-year time series of total water storage changes derived from high-precision superconducting gravimeter observations in a headwater catchment in Southern Germany. In combination with hydro-meteorological data, we examine the relationship between gravity-derived water storage changes, climate, and river discharge. Distinct seasonal water storage dynamics observed by the gravimeter are strongly related to the meteorological forcing, in particular evapotranspiration. Intra-annual water storage variations demonstrate that the simplifying assumption of water storage averaging to zero at the annual scale is not valid for this catchment. At the event-scale, gravimeters provide a measure of the available subsurface water storage capacity, which can be useful for runoff prediction. During the Central European drought in 2003, the gravimeter data show a strong depletion of water storage and a long-term recovery that extended over a period of several years. In comparison to point measurements or different environmental indices, our findings suggest that depth-integrated gravimeter measurements give a more complete picture of the dynamics of a hydrologic system in response to climate variability and extremes. In view of the considerable costs of gravimeters concerning the infrastructure and measurements, we suggest the strategic deployment of gravimeters at selected sites of hydro-meteorological monitoring networks.Citation: Creutzfeldt, B., T. Ferré, P. Troch, B. Merz, H. Wziontek, and A. Güntner (2012), Total water storage dynamics in response to climate variability and extremes: Inference from long-term terrestrial gravity measurement,

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Section: Study Area and Datamentioning

confidence: 99%

Total water storage dynamics in response to climate variability and extremes: Inference from long‐term terrestrial gravity measurement

et al. 2012

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“…It has the potential to detect almost all signatures with periods ranging from serveral seconds related to coseimic movements to several years related to the variations in the Earth's rotation, even the phenomena associated with the secular tectonic movements of local crust, such as the the Earth's free oscillations (Banka and Crossley 1999;Van Camp 1999;Lei et al 2005;Park et al 2005), the Earth's tides (Sun et al 2001;Xu et al 2004a), the load effects of barometric pressure (Sun and Lou 1998), the nearly diurnal resonance (Defraigne et al 1994;Xu et al 2002), translational oscilations of the solid inner core (Smylie 1992;Courtier et al 2000;Rosat et al 2003;Xu et al 2010), Polar motion (Loyer et al 1999;Xu et al 2004b), secular crust deformation due to earthquakes or other reasons Imanishi et al 2004;Richter et al 2004;Xu et al 2008) and so on. As a result, a significant scientific project, i.e., the Global Geodynamics Project, has been carried out since 1997 in order to investigate global and local dynamic problems using continuous gravity data from a worldwide network of superconducting gravimeters Crossley 2004;Crossley and Hinderer 2009). This project has produced numerous scientific achievements and benefited many disciplines.…”

Section: Introductionmentioning

confidence: 99%

Results of Gravity Observations Using a Superconducting Gravimeter at the Tibetan Plateau

Sun¹,

Xu²,

Chen³

et al. 2013

Terr. Atmos. Ocean. Sci.

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The tidal and nontidal gravity change characteristics in the Tibetan Plateau region were investigated using the continuous gravity measurements recorded with a superconducting gravimeter (SG) installed in Lhasa from December 8, 2009 to September 30, 2011. The results indicated that the precision of the tidal gravity observations with the SG in Lhasa was very high. The standard deviation of the harmonic analysis for the gravity tides was 0.498 nm s -2 , and the uncertainties of amplitude factors in the four main tidal waves (i.e., O 1 , K 1 , M 2 and S 2 ) were better than 0.002%. In addition, the diurnal gravity tide observations clearly revealed a pattern of nearly diurnal resonance. As a result, it is affirmed that the station should act as a local tidal gravity reference in the Tibetan Plateau and its adjacent regions. The load effects of oceanic tides are so weak that the resulting perturbation in the gravimetric factors is less than 0.6%. However, the load effects of the local atmosphere on either the tidal or the nontidal gravity observations are significant, although no seasonal variations have been found. After removing the atmospheric effects, the standard deviation of the harmonic analysis for the gravity tides decreased obviously from 4.160 to 0.498 nm s -2 . Having removed the load effects of oceanic tides and local atmosphere, it is found that the tidal gravity observations are significantly different from those expected theoretically, which may be related to active tectonic movement and extremely thick crust in the Tibetan Plateau region. In addition, the Earth's free oscillations excited by 2011 Tohoku-Oki M w 9.0 Earthquake were successfully detected.

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“…The ground validation of such gravity changes by superconducting gravimetry will require an OTL model accurate to the same level. Other examples of high-precision applications of SG can be found in Crossley and Hinderer (2009). OTL corrections in such applications are critical to achieving optimal results.…”

Section: Introductionmentioning

confidence: 99%

SGOTL: A Computer Program for Modeling High-Resolution, Height-Dependent Gravity Effect of Ocean Tide Loading

Hwang¹,

Huang²

2012

Terr. Atmos. Ocean. Sci.

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SGOTL, a computer package coded in FORTRAN, has been developed to model the gravity effect due to ocean tide loading (OTL), especially for a coastal station with large ocean tides. SGOTL uses a regional and a global tide model to account separately for near (inner) and far (outer) zone contributions, and optimizes an inner-zone region and grid interval for numerical convolution. Height dependent Green's functions for Newtonian and elastic effects are developed. The coastline is defined by the full-resolution GMT shoreline, and optionally a digital elevation model (DEM). A case study using gravity observations at the Hsinchu superconducting gravity station and some offshore islands around the Taiwan Strait suggests that SGOTL outperforms some selected global OTL programs and achieves an accuracy of 0.1 μGal for 8 leading tidal constituents.

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A review of the GGP network and scientific challenges

Cited by 26 publications

References 20 publications

Total water storage dynamics in response to climate variability and extremes: Inference from long‐term terrestrial gravity measurement

Total water storage dynamics in response to climate variability and extremes: Inference from long‐term terrestrial gravity measurement

Results of Gravity Observations Using a Superconducting Gravimeter at the Tibetan Plateau

SGOTL: A Computer Program for Modeling High-Resolution, Height-Dependent Gravity Effect of Ocean Tide Loading

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