ITG-GRACE: Global Static and Temporal Gravity Field Models from GRACE Data

Abstract

More than 4 years of GRACE data were used to determine the gravity field model ITG-Grace03 s. The solution consists of three parts: a static high resolution model up to a spherical harmonic degree of 180, temporal variations up to degree 40 and the full variance-covariance matrix for the static solution. The temporal gravity field variations are parameterized by continuous basis functions in the time domain. The physical model of the gravity field recovery technique is based on Newton’s equation of motion, formulated as a boundary value problem in the form of a Fredholm type integral equation. The principal characteristic of this method is the use of short arcs of the satellite’s orbit in order to avoid the accumulation of modeling errors and a rigorous consideration of correlations between the range observations in the subsequent adjustment procedure.