The first Gravity Geoid Model for Israel

This research introduces the formation of a Geoid model that is based on terrestrial gravity measurements in Israel and its surroundings, together with shipborne gravity measurements and altimetry data over the Mediterranean Sea, using the EIGEN-6C4 as the reference earth gravity model – the first of a kind effort done in Israel to construct such a model. A challenging aspect for establishing this model for this area - that does not exist elsewhere in the world - is that approximately 20% of Israel's land area is located below sea level, some of which is minus 430 meters, mainly along the Dead Sea Rift. This unique topography requires new and challenging computation theories for gravimetric Geoid determination.

The results yield a standard deviation value of the gravimetric Geoid of 5.7 cm. The model is also successfully calculated in areas with a negative orthometric altitude, which proves for the first time the potential of the developed methodology of obtaining an accurate geoid model. The hybrid Geoid model significantly improves these values, where the standard deviation value is reduced to 2 cm with an error range of 22 cm. The hybrid Geoid model retains the orthometric datum of the control points while relying on gravimetric data to provide better gradient information about the area. The high accuracy of the hybrid Geoid model will allow the integration of the official national Geoid model and the new gravimetric Geoid model to support precise GNSS measurements used for precise infrastructure engineering projects. The gravimetric geoid can recreate a role with other local gravity models developed by countries surrounding Israel.