Assessment of High-Resolution Global Gravity Field Models and Their Application in Quasi-geoid Modelling in Finland

2014 ◽  
pp. 51-58 ◽  
Author(s):  
Mirjam Bilker-Koivula
Keyword(s):  
High Resolution ◽  
Gravity Field ◽  
Global Gravity ◽  
Gravity Field Models

scholarly journals Evaluation of Gravity Data Derived from Global Gravity Field Models Using Terrestrial Gravity Data in Enugu State, Nigeria

2018 ◽  
Vol 8 (1) ◽  
pp. 145-153 ◽  
Author(s):  
O.I. Apeh ◽  
E.C. Moka ◽  
V.N. Uzodinma
Keyword(s):  
Gravity Field ◽  
Gravity Data ◽  
Gravity Anomalies ◽  
Mean Square ◽  
Bouguer Gravity ◽  
Bouguer Anomalies ◽  
The Earth ◽  
Global Gravity ◽  
Enugu State ◽  
Gravity Field Models

Abstract Spherical harmonic expansion is a commonly applied mathematical representation of the earth’s gravity field. This representation is implied by the potential coeffcients determined by using elements/parameters of the field observed on the surface of the earth and/or in space outside the earth in the spherical harmonic expansion of the field. International Centre for Gravity Earth Models (ICGEM) publishes, from time to time, Global Gravity Field Models (GGMs) that have been developed. These GGMs need evaluation with terrestrial data of different locations to ascertain their accuracy for application in those locations. In this study, Bouguer gravity anomalies derived from a total of eleven (11) recent GGMs, using sixty sample points, were evaluated by means of Root-Mean-Square difference and correlation coeficient. The Root-Mean-Square differences of the computed Bouguer anomalies from ICGEMwebsite compared to their positionally corresponding terrestrial Bouguer anomalies range from 9.530mgal to 37.113mgal. Additionally, the correlation coe_cients of the structure of the signal of the terrestrial and GGM-derived Bouguer anomalies range from 0.480 to 0.879. It was observed that GECO derived Bouguer gravity anomalies have the best signal structure relationship with the terrestrial data than the other ten GGMs. We also discovered that EIGEN-6C4 and GECO derived Bouguer anomalies have enormous potential to be used as supplements to the terrestrial Bouguer anomalies for Enugu State, Nigeria.

Quality assessment of global gravity field models in coastal zones: A case study using astrogeodetic vertical deflections in Istanbul, Turkey

2020 ◽  
Vol 64 (3) ◽  
pp. 306-329 ◽  
Author(s):  
Müge Albayrak ◽  
Christian Hirt ◽  
Sébastien Guillaume ◽  
Kerem Halicioglu ◽  
M. Tevfik Özlüdemir ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Gravity Field ◽  
Coastal Zones ◽  
Global Gravity ◽  
Gravity Field Models

Studies of spectral characteristics of CHAMP, GRAСE, and GOCE global gravity field models

2014 ◽  
Vol 22 (4) ◽  
pp. 34-44
Author(s):  
A.P. Karpik ◽  
◽  
V.F. Kanushin ◽  
I.G. Ganagina ◽  
D.N. Goldobin ◽  
...  
Keyword(s):  
Gravity Field ◽  
Spectral Characteristics ◽  
Global Gravity ◽  
Gravity Field Models

High-resolution combined global gravity field modelling – The d/o 5,400 XGM2020 model

2020 ◽  
Author(s):  
Philipp Zingerle ◽  
Roland Pail ◽  
Thomas Gruber
Keyword(s):  
High Resolution ◽  
Gravity Field ◽  
Gravity Anomalies ◽  
Normal Equation ◽  
Terrestrial Gravity ◽  
Gravity Field Modelling ◽  
Field Modelling ◽  
Global Gravity ◽  
Very High ◽  
Block Diagonal

<p>Within this contribution we present the new experimental combined global gravity field model XGM2020. Key feature of this model is the rigorous combination of the latest GOCO06s satellite-only model with global terrestrial gravity anomalies on normal equation level, up to d/o 2159, using individual observation weights. To provide a maximum resolution, the model is further extended to d/o 5400 by applying block diagonal techniques.</p><p>To attain the high resolution, the incorporated terrestrial dataset is composed of three different data sources: Over land 15´ gravity anomalies (by courtesy of NGA) are augmented with topographic information, and over the oceans gravity anomalies derived from altimetry are used.  Corresponding normal equations are computed from these data sets either as full or as block diagonal systems.</p><p>Special emphasis is given to the novel processing techniques needed for very high-resolution gravity field modelling. As such the spheroidal harmonics play a central role, as well as the stable calculation of associated Legendre polynomials up to very high d/o. Also, a new technique for the optimal low-pass filtering of terrestrial gravity datasets is presented.</p><p>On the computational side, solving dense normal equation systems up to d/o 2159 means dealing with matrices of the size of about 158TB. Handling with matrices of such a size is very demanding, even for today’s largest supercomputers. Thus, sophisticated parallelized algorithms with focus on load balancing are crucial for a successful and efficient calculation.</p>

Direct BEM for high-resolution global gravity field modelling

2010 ◽  
Vol 54 (2) ◽  
pp. 219-238 ◽  
Author(s):  
Róbert Čunderlík ◽  
Karol Mikula
Keyword(s):  
High Resolution ◽  
Gravity Field ◽  
Gravity Field Modelling ◽  
Field Modelling ◽  
Global Gravity
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