The development and evaluation of the Earth Gravitational Model 2008 (EGM2008)

EGM2008 is a spherical harmonic model of the Earth's gravitational potential, developed by a least squares combination of the ITG‐GRACE03S gravitational model and its associated error covariance matrix, with the gravitational information obtained from a global set of area‐mean free‐air gravity anomalies defined on a 5 arc‐minute equiangular grid. This grid was formed by merging terrestrial, altimetry‐derived, and airborne gravity data. Over areas where only lower resolution gravity data were available, their spectral content was supplemented with gravitational information implied by the topography. EGM2008 is complete to degree and order 2159, and contains additional coefficients up to degree 2190 and order…