On March 31, 2006 the high-resolution gravity field model
EIGEN-GL04C has been released. This model is a
combination of GRACE and LAGEOS mission plus 0.5 x 0.5 degrees gravimetry
and altimetry surface data and is complete to degree and order
360 in terms of spherical harmonic coefficients.
High-resolution combination gravity models are essential for all applications
where a precise knowledge of the static gravity potential and its
gradients is needed in the medium and short wavelength spectrum.
Typical examples are precise orbit determination of geodetic
and altimeter satellites or the study of the Earth's crust and mantle mass
distribution.
But, various geodetic and altimeter applications request also a
pure satellite-only gravity model. As an example, the ocean dynamic
topography and the derived geostrophic surface currents, both
derived from altimeter measurements and an oceanic geoid,
would be strongly correlated with the mean sea surface height
model used to derive terrestrial gravity data for the combination model.
Therefore, the satellite-only part of EIGEN-GL04C is provided
here as EIGEN-GL04S1. The contributing GRACE and Lageos
data are already described in the
EIGEN-GL04C description. The satellite-only model
has been
derived from EIGEN-GL04C by reduction of the terrestrial normal
equation system and is complete up to degree and order 150.
up
