The Indian Ocean Geoid Low (IOGL) appears as a prominent feature if the geoid is, usual, shown with respect to Earth's reference shape. However, it is relative hydrostatic equilibrium, i.e. including excess flattening, merely regional low on north-south trending belt of geoid. For mantle viscosity structure an increase 2–3 orders magnitude from asthenosphere lower mantle, which suitable explain...

[1] The equipotential figures of Earth (residual geoid), and of Mars (areoid) are characterized by pairs of elevated and pairs of depressed antipodal equatorial regions. Elevated regions of the residual geoid lie vertically above the two Large Low Shear Wave Velocity Provinces (LLSVPs) on the Core Mantle Boundary (CMB). There is evidence that the LLSVPs are dense, physicochemically distinct, an...

The mean dynamic topography of the surface of the North Atlantic is estimated using an inverse model of the ocean circulation constrained by hydrographic and altimetric observations. In the North Atlantic, altimetric observations have no signi®cant impact on the topography estimate because of the limited precision of available geoid height models. They have a signi®cant impact, however, when un...

The orbital analysis of artificial Earth satellites have revealed the existence of a strong third harmonic in the gravitational potential of the Earth which gives its ‘pear-shape’ in the averaged meridional section. Various attempts to explain this pear-shape based on physical principles have proved to be inconclusive. In this study, a new approach based upon statistical correlation between var...

precise geoid determination on islands suffers from the lack of accurate gravity data on the open seas. nowadays, sub-microgal accuracy for the land gravity observations is obtainable. but the sea gravity data which are collected via shipborne techniques, due to the measuring environment at sea area, are usually highly noisy and are contaminated with various systematic errors. on the other hand...

one of the difficulties in using absolute altitudes is the separation between the mean open sealevel and geoid. theoretically, geoid is the base level in absolute altitudes, but practically, the mean open sealevel is used as a base level for absolute altitudes. the difference between these two levels is called as the seasurface topography. in this research, it is dealt the mean sea level modeli...

We consider the problem of local (quasi-)geoid modelling from terrestrial gravity anomalies. Whereas this problem is uniquely solvable (up to spherical harmonic degree one) if gravity anomalies are globally available, the problem is non-unique if gravity anomalies are only available within a local area, which is the typical situation in local/regional gravity field modelling. We derive a mathem...

Gravimetric geoid computation is often based on modified Stokes’s integration, where Stokes’s integral is evaluated with some stochastic or deterministic kernel modification. Accurate numerical evaluation of Stokes’s integral requires the modified kernel to be integrated across the area of each discretised grid cell (mean kernel). Evaluating the modified kernel at the centre of the cell (point ...

With the gravity eld and steady-state ocean circulation explorer (GOCE) (preferably combined with the gravity eld and climate experiment (GRACE)) a new generation of geoid models will become available for use in height determination. These models will be globally consistent, accurate (<3 cm) and with a spatial resolution up to degree and order 200, when expressed in terms of a spherical harmoni...

using satellite altimetry derived mean sea level (msl), geopotential coefficients in terms of ellipsoidal harmonics from recent satellite gravimetry missions, gravity potential values over a grid consisting of 33,486 points at global sea areas are computed and the mean value of the gravity potential at msl is calculated as a new geoid’s potential value. in this way we have exactly followed the ...