GGMCalc a software for calculation of the geoid undulation and the height anomaly using the iteration method, and classical gravity anomaly

2012 ◽  
Vol 5 (2) ◽  
pp. 123-136 ◽  
Author(s):  
Siamak Moazezi ◽  
Hossein Zomorrodian
Keyword(s):  
Gravity Anomaly ◽  
Iteration Method ◽  
Geoid Undulation ◽  
Height Anomaly ◽  
Classical Gravity

scholarly journals Computing height anomalies using spherical harmonic coefficients at certain degrees and orders in long-wavelength components

2016 ◽  
Vol 19 (2) ◽  
pp. 11-18
Author(s):  
Bao-Binh Luong
Keyword(s):  
Spherical Harmonic ◽  
Geoid Undulation ◽  
Height Anomaly ◽  
Reliability Of Results ◽  
Long Wavelength ◽  
Basic Quantity ◽  
Near Future

Height anomaly / geoid undulation) is a basic quantity in geodesy. It can be directly measured from GPS and leveling or computed from gravitational models. This paper introduces program GeoH to compute height anomalies using spherical harmonic coefficients at certain degrees and orders in longwavelength components. By reasonably comparing with official values of EGM96, the reliability of results from GeoH is proved for the long-wavelength components, and then can be applied in the “remove-restore” technique for determining Vietnamese quasi-geoid in near future.

scholarly journals Centimeter Precision Geoid Model for Jeddah Region (Saudi Arabia)

2020 ◽  
Vol 12 (12) ◽  
pp. 2066
Author(s):  
Alessandra Borghi ◽  
Riccardo Barzaghi ◽  
Omar Al-Bayari ◽  
Suhail Al Madani
Keyword(s):  
Gravity Field ◽  
Ocean Circulation ◽  
Gravity Data ◽  
Independent Set ◽  
Geoid Undulation ◽  
Height Anomaly ◽  
Geoid Model ◽  
Satellite Gravity ◽  
Earth’S Gravity Field ◽  
Long Wavelength

In 2014, the Jeddah Municipality made a call for an estimate of a centimetric precision geoid model to be used for engineering and surveying applications, because the regional geoid model available at that time did not reach a sufficient precision. A project was set up to this end and dedicated sets of gravity and Global Positioning System (GPS)/levelling data were acquired in the framework of this project. In this paper, a thorough analysis of these newly acquired data and of the last available Global Gravity Field Models (GGMs) has been done in order to obtain a geoid undulation estimate with the prescribed precision. In the framework of the Remove–Compute–Restore (RCR) approach, the collocation method was used to obtain the height anomaly estimation that was then converted to geoid undulation. The remove and restore steps of the RCR approach were based on GGMs, derived from the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and Gravity Recovery and Climate Experiment (GRACE) dedicated gravity satellite missions, which were used to improve the long wavelength components of the Earth’s gravity field. Furthermore, two different quasi-geoid collocation estimates were computed, based on gravity data only and on gravity plus GPS/levelling data (the so-called hybrid estimate). The best solutions were obtained with the hybrid geoid estimate. This was tested by comparison with an independent set of GPS/levelling geoid undulations that were not included in the computed solutions. By these tests, the precision of the hybrid geoid is estimated to be 3.7 cm. This precision proved to be better, by a factor of two, than the corresponding one estimated from the pure gravimetric geoid. This project has been also useful to verify the importance and reliability of GGMs developed from the last satellite gravity missions (GOCE and GRACE) that have significantly improved our knowledge of the long wavelength components of the Earth’s gravity field, especially in areas with poor coverage of terrestrial gravity data. In fact, the geoid models based on satellite-only GGMs proved to have a better performance, despite the lower spatial resolution with respect to high-resolution models (i.e., Earth Gravitational Model 2008 (EGM2008)).

Alternating iteration method for interacting multiple crack problems

1999 ◽  
Vol 22 (9) ◽  
pp. 743-752 ◽  
Author(s):  
J. H. Kuang ◽  
C. K. Chen
Keyword(s):  
Iteration Method ◽  
Multiple Crack ◽  
Crack Problems
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