EGY-HGM2016: an improved hybrid local geoid model for Egypt based on the combination of GOCE-based geopotential model with gravimetric and GNSS/levelling measurements

Faculty Engineering Year: 2017
Type of Publication: ZU Hosted Pages:
Authors:
Journal: Arab J Geosci Springer Volume:
Keywords : EGY-HGM2016: , improved hybrid local geoid model    
Abstract:
An improved hybrid gravimetric geoid model for Egypt, EGY-HGM2016, has been recently computed implementing the least-squares collocation (LSC) method through the remove-compute-restore (RCR) procedure. The computation of EGY-HGM2016 involves different datasets in terms of gravity anomalies determined from the GOCE (gravity field and steady-state ocean circulation explorer)- based global geopotential model (SPW-R4) up to d/o 200 and EGM2008 from d/o 201 to 720 combined with terrestrial gravity datasets in terms of 2140 gravity field anomalies and about 121,480 marine surface gravity anomalies. In addition, orthometric heights from 17 GPS/levelling measurements have been considered during the modelling process to improve the determination of the hybrid gravimetric geoid over the Egyptian region. The EGY-HGM2016 model estimated over Egypt provides geoid heights that are ranging from 7.677 to 21.095 m with a standard deviation (st. dev.) of about 2.534min the northwest of the country excluding the involvement of the orthometric heights from GPS/levelling measurements. When the later dataset is considered during the implementation of LSC process, hybrid residual height anomalies ranging from −1.5 to +0.9 m, with a mean of 0.22 m and a st. dev. of 0.17 m, are obtained. Comparison of the predicted hybrid gravimetric geoid with the corresponding ones obtained from EGM2008, GOCE-based SPW R4 model, and GPS/levelling reveals considerable improvements of our EGY-HGM2016 model over Egypt.
   
     
 
       

Author Related Publications

  • Mohammed Ahmed Ali Alashkar , "Determination of local gravimetric geoid model over Egypt using LSC and FFT estimation techniques based on different satellite- and ground-based datasets", Taylor & Francis, 2021 More
  • Mohammed Ahmed Ali Alashkar , "On the Accuracy Assessment of the Latest Releases of GOCE Satellite-Based Geopotential Models with EGM2008 and Terrestrial GPS/Levelling and Gravity Data over Egypt", Scientific Research Publishing, 2016 More
  • Mohammed Ahmed Ali Alashkar , "Accuracy Assessment of GPS Leveling Applications: Case Study, North West Lake Nasser Aswan, Egypt", Ain Shams University, Faculty of Engineering, 2016 More
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