Regional quasigeoid determination: an application to Arctic gravity project
Journal Title: Геодинаміка - Year 2015, Vol 18, Issue 1
Abstract
Purpose. Investigation to study quasigeoid computations based on the regional gravimetric data and different types of nonorthogonal basis functions was assessed to be important. When measurements from only restricted regions of the Earth surface are available, global spherical harmonics loose their orthogonality in a limited region, so the determination of the coefficients of the model, usually by using the least squares method, is numerically unstable. In spite of this fact, there is a specific solution for Laplace equation for the situation of a spherical cap when the boundary conditions are appropriate. Methods. Our solution uses the gravity anomalies in the Arctic area taken from the Arctic Gravity Project (AGP). The method applied on this data set is adjusted spherical harmonic analysis (ASHA). Computation of the quasigeoid heights was performed by the “Remove - Restore” procedure in three steps. On the first step the free air gravity anomalies of the EGM 2008 model up to degree/order 360 were substracted from the initial gravity anomalies of the AGP to get rid of the low frequency gravity field content. On the second step the approximation of the residual gravity anomalies was based on the ASHA method. The construction of the normal equations matrix may lead to the time consuming procedure. For this reason the discrete orthogonality property in longitude for the chosen basis system was taken into account and led to the significant decrease of the computational time of the residual coefficients . On the last step the residual quasigeoid heights (high frequency components of the gravity field) were computed via the residual harmonic coefficients and added to the global contribution of quasigeoid heights taken from the EGM2008 model up to degree/order 360 (low frequency components of the gravity field). Results. Hence the gravity field model was constructed and compared with AGP gravity anomalies. Also the obtained model of quasigeoid heights was compared with quasigeoid heights from 49 GNSS/leveling points. Scientific novelty and practical significance. In this paper the modification of ASHA method was developed, which makes it possible to significantly accelerate the process of computing the unknown coefficients in the construction of local gravitational fields. This allows to compute local gravitational fields of higher orders. It is well known that quasigeoid accuracy depends on the order of model.
Authors and Affiliations
A. N. Marchenko, B. B. Dzhuman
Keywords
Related Articles
- EP ID EP455881
- DOI 10.23939/jgd2015.01.007
- Views 133
- Downloads 0
Peculiarities of the anomalous magnetic field in the areas of hydrocarbon fields in the Carpathian foredeep
Purpose. Identifying of anomalous magnetic field peculiarities upon oil-and-gas bearing structures in the Carpathian Feoredeep and its relationships with oil and gas deposits. Methodology. Measuring of geomagnetic field...
The association of physical properties of deep reservoirs with the geomagnetic field and fault-block tectonics in the Hlynsko-Solokhivskyi oil-and-gas region
Purpose of the study. To study physical properties of the reservoir rocks of Semyrenkivske field in the Hlynsko-Solokhivskyi oil and gas region (OGR) of the Dnipro-Donets Aulacogene with the aim of evaluating their filtr...
"Young platform"- traditional intelligence and reality (geodynamic aspect)
Purpose. Transition of theoretical tectonics to the mobilistic position has changed a notion of the nature of geological processes, and hence approaches to re-comprehesion on the new high-quality level of views of the te...
Spatial correlations of pelite silt rocks in the sedimentary cover of the Novogradskiy block (Volin megablock of the Ukrainian shield)
Purpose. The goal of the research is to identify spatial trends and patterns in concordant bedding of sedimentary rocks, first of all pelite silt rocks of the sedimentary cover of the Ukrainian shield, using the Novograd...
Modeling of vertical movements of tectonic blocks, according to tide gauge observations
Purpose. The purpose of this study: to reconstruct the vertical movements of the earth crust in northern parts of Europe, according to long-term tide gauge observations; to investigate the change of kinematic parameters...