%0 Journal Article
%T 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
%A Mohamed El-Ashquer
%A Basem Elsaka
%A Gamal El-Fiky
%J International Journal of Geosciences
%P 1323-1344
%@ 2156-8367
%D 2016
%I Scientific Research Publishing
%R 10.4236/ijg.2016.711097
%X The Global Geopotential
Models (GGMs) of GOCE (Gravity Recovery and steady-</span><span style=\"font-family:&quot;\"> </span><span style=\"font-family:Verdana;\">state Ocean Circulation Explorer) differ globally as
well as regionally in their accuracy and resolution based on the maximum degree
and order (d/o) of the fully normalized spherical harmonic (</span><i><span style=\"font-family:Verdana;\">SH</span></i><span style=\"font-family:Verdana;\">) coefficients, which express each GGM. The main idea of this study is to
compare the free-air gravity anomalies and quasi geoid heights determined from
several recent GOCE-based GGMs with the corresponding ones from the Earth
Gravitational Model 2008 (EGM2008) over Egypt on the one hand and with
ground-based measurements on the other hand. The results regarding to the
comparison of GOCE-based GGMs with terrestrial gravity and GPS/levelling data
provide better improvement with respect to EGM2008. The 4th release GOCE-based
GGM developed with the use of space-wise solution strategy (SPW_R4)
approximates the gravity field well over the Egyptian region. The SPW_R4 model
is accordingly suggested as a reference model for recovering the long
wavelength (up to SH d/o 200) components of quasi geoid heights when modelling
the gravimetric quasi-geoid over the Egypt. Finally, three types of
transformation models</span><span style=\"font-family:Verdana;\">:</span><span style=\"font-family:Verdana;\"> Four-,
Five- and Seven-parameter transformations have been applied to reduce the data
biases and to provide a better fitting of quasi geoid heights obtained from the
studied GOCE-based GGMs to those from GPS/levelling data. These models reveal
that the standard deviation of vertical datum over Egypt is at the level of
about 32 cm.
%K GOCE-Based GGMs
%K Free-Air Gravity Anomalies
%K GPS/Levelling Data
%K Spectral Enhancement Method (SEM)
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=72361