Regional Gravity Field Research Articles

Unification of European height system realizations

AbstractA suitable representation of the regional gravity field is used to estimate relative offsets between national height system realizations in Europe. The method used is based on a gravimetric approach and benefits from the significant improvements in the determination of the global gravity field by the recent satellite gravity missions the Gravity Recovery and Climate Experiment (GRACE) and the Gravity field and steady-state Ocean Circulation Explorerr (GOCE). The potential of these missions for the unification of height reference frames is analyzed in terms of accuracy and spatial resolution. The results of the gravimetric approach are compared to the independent results of the geodetic leveling approach. Advantages and drawbacks of both methods are discussed.

A crust-scale 3D structural model of the Beaufort-Mackenzie Basin (Arctic Canada)

The Beaufort-Mackenzie Basin was initiated in the Early Jurassic as part of an Arctic rifted passive continental margin which soon after became overprinted by Cordilleran foreland tectonics. Decades of industrial exploration and scientific research in this petroliferous region have produced a wide spectrum of geological and geophysical data as well as geoscientific knowledge. We have integrated available grids of sedimentary horizons, well data, seismic reflection and refraction data, and the observed regional gravity field into the first crust-scale 3D structural model of the Beaufort-Mackenzie Basin. Many characteristics of this model reflect the complex geodynamic and tectonostratigraphic history of the basin.The Mesozoic–Cenozoic sedimentary part of the model comprises seven clastic units (predominantly sandy shales) of which the modelled thickness distributions allow to retrace the well-established history of the basin comprising a gradual north(east)ward shift of the main depocentres as well as diverse phases of localised erosion. As a result of this development, the present-day configuration of the basin reveals that the sedimentary units tend to be younger, more porous, and thus less dense towards the north at a constant depth level.By integrating three refraction seismic profiles and performing combined isostatic and 3D gravity modelling, we have modelled the sub-sedimentary basement of the Beaufort-Mackenzie Basin. The continental basement spans from unstretched domains (as thick as about 42km) in the south to extremely thinned domains (of less than 5km thickness) in the north where it probably represents transitional crust attached to the oceanic crust of the Canada Basin. The uppermost parts of the continental crust are less dense (ρ=2710kg/m3) and most probably made up by pre-Mesozoic meta-sediments overlying a heavier igneous and metamorphic crust (ρ=2850kg/m3).The presented crust-scale 3D structural model shows that the greatest thicknesses of Mesozoic–Cenozoic sediments (almost 17km) are not found in the north where the sub-sedimentary crust is thinnest, but farther south where the crust is thicker and the Moho quite deep. We causally relate the huge amounts of foredeep deposits overlying a Moho depression to a flexural response of the lithosphere to orogenic loading induced by the Brooks Range orogen in the south. Our 3D model provides an ideal base and reference for future numerical studies including reconstructions of the development from a passive margin to a foreland basin and simulations of the present-day thermal field of the basin.

Gravity changes before and after the 2010 Ms7.1 Yushu earthquake

Absolute and relative gravity observations from 1998–2010 from the China Crustal Movement Observation Network, a major national scientific project, have been used to model the gravity field and its variations associated with the April 14, 2010 Ms7 . 1 Yushu earthquake. The evolution of the regional gravity field and its relationship with seismicity before and after the Yushu earthquake are studied. The observed gravity changes are closely related to the active Ganzi-Yushu Fault, and gravity measurements can be used to observe the migration of material accompanying active faults and crustal tectonics. The dynamic variation of the gravity field reflects its evolution prior to and during the Yushu earthquake. The gravity measurements near its epicenter are as large as 80 × 10 − 8 m/s 2 , and they show wave-like increases with time prior to the Yushu earthquake.

Using modern geopotential models in studying vertical deflections in the Arctic

The paper continues analyzing the results of the mathematical modeling of the Earth’s anomalous gravity field in high-latitude regions which are of interest from the viewpoint of Arctic exploration. The structure and the accuracy characteristics of vertical deflections in the Arctic have been studied. The study was conducted with the use of 16 modern Russian and foreign models of spherical harmonics of the Earth’s gravity potential, including the ultrahigh degree model EGM-2008, the first models based on satellite gradiometry data, and the latest Russian model GAO-2012.

Dynamic changes of gravity fields before and after the 2008 Wenchuan earthquake (Ms8.0)

Abstract: The pattern evolution and dynamic mechanism of the dynamic changes of regional gravity fields occurring before and after the Wenchuan M s8.0 earthquake are analyzed, based on five epochs of 1998–2007 mobile gravity data from the middle-south section of the north–south seismic belt, and two epochs of field research data collected after the 2008 Wenchuan earthquake in combination with GPS data, leveling observations, and geotectonic environment data. The regional dynamic gravity changes demonstrate the effects of the eastward flow of solid matter in the Qinghai-Tibetan plateau and the preparation of the 2008 Wenchuan earthquake (2–10 yr). The two most meaningful gravity indicators of the Wenchuan earthquake preparation are the positive (increasing) gravity changes occurring over many years in the southwest epicenter and the large-scale gradient zone of gravity variation, with the cumulative difference between the two sides of the gradient zone of gravity exceeding 200 μGal. The positive gravity changes may facilitate a constant energy accumulation and the gradient belt may support seismic shear breakage. Overall, the gravity changes associated with the earthquake preparation indicate a pattern of accelerating increase-decelerating increase-earthquake occurrence. The Songpan-Ganzi block generally displays a negative gravity change, providing evidence for a local upwarping of the deep crust-mantle and an interior expansion of the deep crust attributable to high temperatures. The viewpoint is consistent with the dilatant mechanism for earthquake preparation.

Temporal gravity changes before the 2008 Yutian Ms7.3 earthquake

Based on the data of the repeated gravity observation network in Chinese mainland since 1998, we analyzed the temporal changes of regional gravity field before the 2008 Yutian M s7. 3 earthquake. The result shows some mid-to-long term (two to ten years) changes during the earthquake’s preparation. Notable features are a gravity increase lasting several years and a relatively large-scaled gradient zone of gravity change, the former indicating a continuous energy accumulation and the latter a possible location of seismic rupture. These gravity changes showed a trend of increase-accelerated increase-decelerated increase, similar to that of the Tangshan M s7. 8 earthquake in 1976. The maximum accumulated gravity change related to the earthquake reached 200 × 10 − 8 ms − 2 .

New Bouguer Gravity Maps of Venezuela: Representation and Analysis of Free-Air and Bouguer Anomalies with Emphasis on Spectral Analyses and Elastic Thickness

A new gravity data compilation for Venezuela was processed and homogenized. Gravity was measured in reference to the International Gravity Standardization Net 1971, and the complete Bouguer anomaly was calculated by using the Geodetic Reference System 1980 and 2.67 Mg/m3. A regional gravity map was computed by removing wavelengths higher than 200 km from the Bouguer anomaly. After the anomaly separation, regional and residual Bouguer gravity fields were then critically discussed in term of the regional tectonic features. Results were compared with the previous geological and tectonic information obtained from former studies. Gravity and topography data in the spectral domain were used to examine the elastic thickness and depths of the structures of the causative measured anomaly. According to the power spectrum analysis results of the gravity data, the averaged Moho depths for the massif, plains, and mountainous areas in Venezuela are 42, 35, and 40 km, respectively. The averaged admittance function computed from the topography and Free-Air anomaly profiles across Mérida Andes showed a good fit for a regional compensation model with an effective elastic thickness of 15 km.

A study of regional gravity field recovery from GOCE vertical gravity gradient data in the Auvergne test area using collocation

Gravity field and steady-state Ocean Circulation Explorer (GOCE) is the first satellite mission that observes gravity gradients from the space, to be primarily used for the determination of high precision global gravity field models. However, the GOCE gradients, having a dense data distribution, may potentially provide better predictions of the regional gravity field than those obtained using a spherical harmonic Earth Geopotential Model (EGM). This is investigated in Auvergne test area using Least Squares Collocation (LSC) with GOCE vertical gravity gradient anomalies (Tzz), removing the long wavelength part from EGM2008 and the short wavelength part by residual terrain modelling (RTM). The results show that terrain effects on the vertical gravity gradient are significant at satellite altitude, reaching a level of 0.11 Eotvos unit (E.U.) in the mountainous areas. Removing the RTM effects from GOCE Tzz leads to significant improvements on the LSC predictions of surface gravity anomalies and quasigeoid heights. Comparison with ground truth data shows that using LSC surface free air gravity anomalies and quasi-geoid heights are recovered from GOCE Tzz with standard deviations of 11 mGal and 18 cm, which is better than those obtained by using GOCE EGMs, demonstrating that information beyond the maximal degree of the GOCE EGMs is present. Investigation of using covariance functions created separately from GOCE Tzz and terrestrial free air gravity anomalies, suggests that both covariance functions give almost identical predictions. However, using covariance function obtained from GOCE Tzz has the effect that the predicted formal average error estimates are considerably larger than the standard deviations of predicted minus observed gravity anomalies. Therefore, GOCE Tzz should be used with caution to determine the covariance functions in areas where surface gravity anomalies are not available, if error estimates are needed.

Rotation of GOCE gravity gradients to local frames

ESA′s GOCE mission aims at improved global and regional gravity field information with high spatial resolution by measuring gravity gradients. A local analysis of the GOCE gravity gradient tensor may benefit from a rotation from the gradiometer reference frame to local reference frames such as the local north oriented reference frame. As the GOCE gravity gradients include accurate and less accurate measured gradients, the point-wise tensor rotation of the GOCE-only measurements may suffer from the projection of the errors of the less accurate gravity gradients onto the accurate gravity gradients. In addition, the GOCE gravity gradients have high accuracy in the measurement bandwidth but low accuracy below, and tensor rotation may cause leakage of the large error below the measurement bandwidth to the measurement bandwidth. Degradation of the rotated gravity gradients is circumvented by replacing the less accurate tensor components, as well as the signal below the measurement bandwidth of the accurate gravity gradients, with model signal. The combination of GOCE and model gravity gradients is performed by determining the effective measurement bandwidth (EMB), that is, the bandwidth in which the integrated signal-to-noise ratio of the GOCE gravity gradients is maximized. We find that the determination of the EMB is relatively independent of the reference gravity field model that is used. The lower bound of the EMB is well below the pre-mission specifications for the four accurate gravity gradients. In addition, we assess how much GOCE contributes to the gravity gradient signal in local frames and how much the model. For the radial gravity gradient the relative GOCE contribution is 98 per cent on average, whereas this is 65-97 per cent for the other gravity gradients. These numbers strongly depend on the local frame under consideration and on the geographical position.

Detailed gravity survey to help seismic microzonation: Mapping the thickness of unconsolidated deposits in Ottawa, Canada

Abstract In this study, measurements of gravity were made to map and model the thickness of Quaternary deposits (sand and clay) overlying Ordovician limestones in a suburb of Ottawa (Orleans, Ontario). Because ground motion amplification is partly related to the thickness of unconsolidated deposits, this work helps refine the assessment of the earthquake damage potential of the area. It also helps the mapping of clay basins, which can locally exceed 100 m in thickness, where ground motion amplification can occur. Previous work, including well log data and seismic methods, have yielded a wealth of information on near-surface geology in Orleans, thereby providing the necessary constraints to test the applicability of gravity modeling in other locations where other methods cannot always be used. Some 104 gravity stations were occupied in an 8 × 12 km test area in the Orleans. Stations were accurately located with differential GPS that provided centimetric accuracy in elevation. Densities of the unconsolidated Quaternary deposits (Champlain Sea clay) determined on core samples and densities determined on limestone samples from outcrops were used to constrain models of the clay layer overlying the higher density bedrock formations (limestone). The gravity anomaly map delineates areas where clay basins attain > 100 m depth. Assuming a realistic density for the Champlain Sea clays (1.9–2.1 g/cm3), the thickness over the higher density bedrock formations (Ordovician carbonate rocks) was modeled and compared with well logs and two seismic reflection profiles. The models match quite well with the information determined from well logs and seismic methods. It was found that gravity and the thickness of unconsolidated deposits are correlated but the uncertainties in both data sets preclude the definition of a direct correlation between the two. We propose that gravity measurements at a local scale be used as an inexpensive means of mapping the thickness of unconsolidated deposits in low-density urban areas. To obtain meaningful results, three conditions must exist. Firstly, elevations of gravity stations must be measured accurately using differential GPS; secondly, that the regional gravity field must be well defined, and thirdly, that the local geology be simple enough to be realistically represented with a two-layer model.

Gravity variation associated with Wenchuan earthquake in western Sichuan

Based on the data of mobile gravity observation from 1998 to 2008 in western Sichuan, spatial dynamic variation results of regional gravity field are obtained. The relationship between the gravity variation features and Wenchuan Ms8.0 earthquake is systematically analyzed. The results show: 1) Gravity variation is closely related to active fault tectonics, and gravity measurement can better reflect material migration following crustal tectonic activity near active fault. 2) The gravity field appeared a wider range regional gravity variation during Wenchuan earthquake occurrence. The dynamic patterns of gravity field demonstrates the evolution process of gravity field: quasi – homogeneous state—non – homogeneous state—earthquake occurrence.

On integral approach to regional gravity field modelling from satellite gradiometric data

Solution of the gradiometric boundary value problems leads to three integral formulas. If we are satisfied with obtaining a smooth solution for the Earth’s gravity field, we can use the formulas in regional gravity field modelling. In such a case, satellite gradiometric data are integrated on a sphere at satellite level and continued downward to the disturbing potential (geoid) at sea level simultaneously. This paper investigates the gravity field modelling from a full tensor of gravity at satellite level. It studies the truncation bias of the integrals as well as the filtering of noise of data. Numerical studies show that by integrating T zz with 1 mE noise and in a cap size of 7°, the geoid can be recovered with an error of 12 cm after the filtering process. Similarly, the errors of the recovered geoids from T xz,yz and T xx-yy, 2xy are 13 and 21 cm, respectively.

Regional gravity field model in Pakistan area from the combination of CHAMP, GRACE and ground data using least squares collocation: A case study

This study describes a methodology of recovery of the Earth’s gravity field from CHAMP and GRACE satellites data in Pakistan using least squares collocation (LSC) based downward continuation technique. The CHAMP height anomalies and GRACE gravity disturbances derived from the observed satellite data have been used in combination solution using LSC with observed gravity values at the Earth surface. The combined covariance functions of height anomalies and/or gravity disturbances at satellite altitudes and observed gravity anomalies at Earth surface have been used as the basis for combination and downward continuation solution. The variance of predicted gravity anomalies from GRACE gravity disturbances is relatively lower than the corresponding results of gravity anomalies from CHAMP height anomalies. This fact may be attributed partly to the amplification of noise and partly to the unstable inverse transformation process of height anomalies to gravity anomalies. The impact of data error variance has been studied in the context of smoothing and noise reduction in the final solution of downward continuation using least squares collocation. The raising of data error suppresses the noise and as a result a smooth final solution is obtained. The prediction results appear to be dependent on the quality of data and goodness of combined covariance function, which are fairly comparable for the CHAMP and GRACE data. The recovered gravity field from satellite data appears to contribute mainly to medium and long wavelength parts of total gravity field spectrum. Due to flexibility of data handling in least squares collocation, this procedure is applicable to any observable of gravity field being at different altitudes and with different data spacing.

Integrated marine gravity field in the Brazilian coast from altimeter-derived sea surface gradient and shipborne gravity

Abstract Sea surface gradients derived from the Geosat and ERS-1 satellite altimetry geodetic missions were integrated with marine gravity data from the National Geophysical Data Center and Brazilian national surveys. Using the least squares collocation method, models of free-air gravity anomaly and geoid height were calculated for the coast of Brazil with a resolution of 2′ × 2′. The integration of satellite and shipborne data showed better statistical results in regions near the coast than using satellite data only, suggesting an improvement when compared to the state-of-the-art global gravity models. Furthermore, these results were obtained with considerably less input information than was used by those reference models. The least squares collocation presented a very low content of high-frequency noise in the predicted gravity anomalies. This may be considered essential to improve the high resolution representation of the gravity field in regions of ocean–continent transition.

Results of the gravity field interpretation in the Turčianska Kotlina Basin

The paper deals with the quantitative interpretation of the gravity field in the Turcianska Kotlina Basin. The interpretation was done by means of the application of the 2D density modelling method using the GM-SYS software. Geophysical constraints of the density models are represented by the existing geophysical measurements and in- terpretations. The Turcianska Kotlina Basin in the picture of the regional gravity field is characterized by the local gravity low with amplitude of about 12 mGal. The source of this gravity low is low density Tertiary sediments, which fill the basin. From the Tertiary sediments the Neogene sediments play dominant role in observed gravity, because their gravity effects are considerably larger in comparison with the gravity effects of the Pale- ogene sediments. The contacts between the Mala Fatra and Vel'kaF atra Mts., and the Turcianska Kotlina Basin are characterized by the significant gravity gradients. They re- flect tectonic contact between the basin and crystalline core mountains. In the Turcianska gravity low we can see along the Profile TK-AL three local gravity lows. The highest local gravity low is explained by the largest thickness of the Tertiary sediments. Another two local gravity lows are also characterised by thicker layers of the Tertiary sediments. Den- sity models assume that the eastern (western) part of the basin basement is built by the Mesozoic (crystalline) rocks. In the central part of the Profile TK-BL the thick Paleogene sedimentary filling (more than 1 km) compensates the deepest part of the Pretertiary basement. Density model along the Profile TK-BL does not suggest a presence of the Paleogene sediments in the basin filling. It is also indicated that the Mesozoic rocks un- derlie the Tertiary sediments. The Pretertiary basement was interpreted in the depths from 0 km up to the 2 km. Note that all geological structures (blocks) are sliding from the East to the West. The dipping of the Mala Fatra Mts. is steeper than in a case of the Vel'ka Fatra Mts. The anomalous bodies observed on the western part of the basin result from the alluvial and detrital cones. Their presence and gravity effect can be observed mainly on the eastern slope of the MalaF atra Mts.

The ice age paleo-channel Ellerbeker Rinne an integrated 3D gravity study

In the framework of a joint field work with partners of the Landesamt fur Landwirtschaft, Umwelt und landliche Raume (LLUR, the former LANU; Flintbek, Germany) and the Leibniz-Institut fur Angewandte Geophysik (LIAG; Hannover, Germany) gravity measurements have been conducted in July 2005 by members of a student course Geophysical field exercise in the area of the Ellerbek paleo-channel near Tangstedt. At approximately 450 stations complete Bouguer anomalies have been calculated. The error of gravity anomaly accounts for 2 x 10(-7) m/s(2) (max.) to -8 x 10(-7) m/s(2) (min.). The gravity field of the region is affected by a strong regional gravity field, which is caused by salt structures. Therefore, a regional field was calculated which based on a regional survey of the State Geodetic Survey. It was subtracted from the Bouguer field and a slightly negative residual field (-1.0 to -1.5 x 10(-5) m/s(2)) resulted in the area of the Ellerbek paleo-channel. It was analysed and interpreted by curvature algorithms, Euler deconvolution and 3D modelling. Euler deconvolution and curvature result in a depth of max. 400 m for this part of the Ellerbek paleo-channel; clusters of Euler source points were also calculated for depths of 130 m and 220 m which points to rather inhomogeneous infill of the channel. The compiled 3D density model was constrained by the seismic profile P3 of LIAG and borehole information. The model explains the positive anomaly north of Tangstedt (> 1.5 x 10(-5) m/s(2)) With a high density body (Geschiebemergel; boulder clay) of 300 kg/m(3) density contrast to the sedimentary infill of the paleo-channel which has its bottom at 200 m depth.

Application of GOCE data for regional gravity field modeling

Abstract In principle, every component of a disturbing gravity gradient tensor measured in a satellite orbit can be used to obtain gravity anomalies on the Earth’s surface. Consequently, these can be used in combination with ground or marine data for further gravity field modeling or for verification of satellite data. Theoretical relations can be derived both in spectral and spatial forms. In this paper, we focus on the derivation of a spatial integral form in the geocentric spherical coordinates that seems to be the most convenient one for regional gravity field modeling. All of the second partial derivatives of the generalized Stokes’s kernel are derived, and six surface Fredholm integral equations are formulated and discretized. The inverse problems formulated for particular components clearly reveal different behaviors in terms of numerical stability of the solution. Simulated GOCE data disturbed with Gaussian noise are used to study the performance of two regularization methods: truncated singular value decomposition and ridge regression. The optimal ridge regression method shows slightly better results in terms of the root mean squared deviation of the differences from the exact solution.

Improved geoid model determination for Japan from GRACE and a regional gravity field model

Abstract A highly improved gravimetric geoid model for Japan, JGEOID2008, is developed on a 1×1.5 arc-minute grid by combining a GRACE (the Gravity Recovery And Climate Experiment)-based global geopotential model, GGM02C, surface (land and ship-borne) gravity measurements, and an altimetry-derived marine gravity model, KMS2002. In the combination, a semidiscrete two-dimensional wavelet analysis/reconstruction method is employed, selecting the spatial wavelength signals of the highest quality out of the respective data sets. Intercomparison with GPS/leveling geoid undulations shows substantial improvement of JGEOID2008 over the previous model, JGEOID2004, and reveals that the systematic errors at long wavelengths contained in JGEOID2004 have been effectively removed. Deviations of JGEOID2008 from the mean sea surface height at tidal stations on isolated islands were comparable to the differences in the sea surface dynamic heights (SSDH) in the Japan Sea, the Nansei Islands and the Izu Island chain from that in Tokyo Bay. The deviations show good agreement with SSDH features estimated from oceanographic observation, indicating that JGEOID2008 has an accuracy within 10 cm. The geoid model is strongly expected to serve as a reference in ocean dynamics studies.

Bottom to top lithosphere structure and evolution of western Eger Rift (Central Europe)

We present model of the structure and development of the entire lithosphere beneath the western Eger Rift (ER). Its crustal architecture and paths of volcanic products are closely related to sutures/boundaries of uppermost mantle domains distinguished by different orientations of olivine fabric, derived from 3-D analysis of seismic anisotropy. Three different fabrics of the mantle lithosphere belong to the Saxothuringian (ST), Tepla-Barrandian (TB) and Moldanubian (MD) microplates assembled during the Variscan orogeny. Dipping fossil (pre-assembly) olivine orientations, consistent within each unit, do not support any voluminous mantle delamination. The variable rift structure and morphology depend on the character of the pre-rift suture between the northern ST unit and the TB/MD units in the southern rift flank. The proper rift with typical graben morphology has developed above the steep lithosphere-scale suture between the ST and TB units. This subduction-related boundary originated from the closure of the ST Ocean. Parts of the crust and mantle lithosphere were dragged there into asthenospheric depths and then rapidly uplifted. The suture is marked by abrupt change in the mantle fabric and sharp gradients in regional gravity field and in metamorphic grade. The secular TB-side-down normal movement is reflected in deep sedimentary basins, which developed since the Carboniferous to Cenozoic and in topography. The graben morphology of the ER terminates above the “triple junction” of the ST, TB and MD mantle lithospheres. The junction is characterized by offsets of surface boundaries of the tectonic units from their mantle counterparts indicating a detachment of the rigid upper crust from the mantle lithosphere. The southwest continuation of the rift features in Bavaria is expressed in occurrences of Cenozoic sediments and volcanics above an inclined broad transition zone between the ST and MD lithospheres. Schematic scenario of evolution of the region consists mainly of a subduction of the ST lithosphere to depths around 140 km, exhumation of HP-HT rocks and the post-tectonic granitoid plutonism.

Triangulated spherical splines for geopotential reconstruction

We present an alternate mathematical technique than contemporary spherical harmonics to approximate the geopotential based on triangulated spherical spline functions, which are smooth piecewise spherical harmonic polynomials over spherical triangulations. The new method is capable of multi-spatial resolution modeling and could thus enhance spatial resolutions for regional gravity field inversion using data from space gravimetry missions such as CHAMP, GRACE or GOCE. First, we propose to use the minimal energy spherical spline interpolation to find a good approximation of the geopotential at the orbital altitude of the satellite. Then we explain how to solve Laplace’s equation on the Earth’s exterior to compute a spherical spline to approximate the geopotential at the Earth’s surface. We propose a domain decomposition technique, which can compute an approximation of the minimal energy spherical spline interpolation on the orbital altitude and a multiple star technique to compute the spherical spline approximation by the collocation method. We prove that the spherical spline constructed by means of the domain decomposition technique converges to the minimal energy spline interpolation. We also prove that the modeled spline geopotential is continuous from the satellite altitude down to the Earth’s surface. We have implemented the two computational algorithms and applied them in a numerical experiment using simulated CHAMP geopotential observations computed at satellite altitude (450 km) assuming EGM96 (nmax = 90) is the truth model. We then validate our approach by comparing the computed geopotential values using the resulting spherical spline model down to the Earth’s surface, with the truth EGM96 values over several study regions. Our numerical evidence demonstrates that the algorithms produce a viable alternative of regional gravity field solution potentially exploiting the full accuracy of data from space gravimetry missions. The major advantage of our method is that it allows us to compute the geopotential over the regions of interest as well as enhancing the spatial resolution commensurable with the characteristics of satellite coverage, which could not be done using a global spherical harmonic representation.