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

Abstract

[1] 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 2159. Over areas covered with high quality gravity data, the discrepancies between EGM2008 geoid undulations and independent GPS/ Leveling values are on the order of AE5 to AE10 cm. EGM2008 vertical deflections over USA and Australia are within AE1.1 to AE1.3 arc-seconds of independent astrogeodetic values. These results indicate that EGM2008 performs comparably with contemporary detailed regional geoid models. EGM2008 performs equally well with other GRACE-based gravitational models in orbit computations. Over EGM96, EGM2008 represents improvement by a factor of six in resolution, and by factors of three to six in accuracy, depending on gravitational quantity and geographic area. EGM2008 represents a milestone and a new paradigm in global gravity field modeling, by demonstrating for the first time ever, that given accurate and detailed gravimetric data, a single global model may satisfy the requirements of a very wide range of applications.

Mantle origin of the Emeishan large igneous province (South China) from the analysis of residual gravity anomalies

“…The overall error derives from uncertainties in: (1) the measured gravity and (2) the estimated thickness and density of (a) the sediment; (b) the crystalline basement; (c) the upper crust; (d) the lower crust; and (e) the mantle lid. Of all these factors, the error associated with the observed satellite gravity is the smallest one, as it amounts to only 5 mGal (Pavlis et al, 2008(Pavlis et al, , 2012. However, the other factors may give rise to larger errors, with a magnitude of 10 mGal or more.…”

“…Pavlis et al (2008Pavlis et al ( , 2012, who presented the Earth Gravitational Model (EGM2008), computed the original Bouguer gravity over South China and surrounding region. This model has a grid spacing of 2.5 × 2.5 arc-minute in both land and ocean.…”

Three‐dimensional density modeling of the EGM2008 gravity field over the Mount Paekdu volcanic area

“…The global gravity field model provides a basis for three-dimensional (3-D) gravity modeling to constrain the location of the LVZ and to analyze the magmatic system. The EGM2008-derived gravity field has an average resolution of 10 km [Pavlis et al, 2012]. In this study, the gravity model is used to resolve the volcanic structures at local to regional scales.…”

Investigating the effect of tide parameterization and gravity field models on SLR solutions

“…The EGM2008 model reported by Pavlis et al (2012) is a high-resolution (∼10 km) combined global gravity field model released by the US National Geospatial Intelligence Agency (NGA). This model was computed up to degree and order 2160 with additional spherical harmonic coefficients up to degree 2190 and order 2160.…”

“…This model was computed up to degree and order 2160 with additional spherical harmonic coefficients up to degree 2190 and order 2160. It incorporated data from GRACE mission (Mayer-Guerr 2007), topographic data (Pavlis et al 2007), altimetry data and gravity observations on land areas (Pavlis et al 2007(Pavlis et al , 2012.…”