Development and Validation of a Regional Geoid Model for the Syrian Arab Republic

Abstract:

While the satellite gravity missions yield a long-wavelength geoid, the altimetric sea surface height
measurements provide retrieval of mesoscale and short-wavelength marine geoid and gravity. That
makes the satellite altimetry important for geoid modeling. This study is an attempt to develop a
marine geoid model for Syria and deriving marine gravity anomalies, which can be used to achieve
better accuracy in computing the terrestrial geoid as the number of terrestrial gravity data points
in the study area is not sufficient for achieving cm-level accuracy. The marine geoid which computed by
combining nine satellite altimetric missions (ERS-1, 2, Jason-1, 2, 3, GFO, SARAL, Topex/Poseidon,
Envisat) is used for generating the along-track vertical deflection components, which in turn used
to obtain north and west component of the vertical deflection. The later is converted to the marine
gravity anomalies using the Vening-Meinesz formula. The marine gravity is validated by comparing it
to shipborne gravity which downloaded from International Gravimetric Bureau (BGI). The altimetric
gravity anomaly can be combined with the airborne and land gravity anomaly to generate marine
and land geoid for Syria.

Keywords— Marine geoid, gravity anomaly, Syria, Mean Dynamic Topography, Mean Sea Surface,
multi-mission altimetry, vertical deflection.