Global atmospheric effects on the gravity field quantities

Abstract

We compile  the global  maps  of atmospheric effects  on the gravity field quantities  using the spherical harmonic representation of the gravitational field.   A simple atmospheric density distribution is assumed within  a lower  atmosphere (< 6 km).   Dis- regarding temporal and  lateral  atmospheric density variations,  the  radial atmospheric density model is defined as a function  of the nominal  atmospheric density at the sea level and the height.  For elevations above  6 km, the atmospheric density distribution from the United  States Standard Atmosphere 1976 is adopted. The 5 × 5 arc-min  global  elevation data  from the ETOPO5 are used to generate the global elevation model coefficients. These coefficients (which  represent the geometry of the lower bound  of atmospheric masses) are utilized  to compute the atmospheric effects  with a spectral resolution complete to degree and  order  180.  The atmospheric effects  on gravity disturbances, gravity anomalies and geoid undulations are evaluated globally on a 1 × 1 arc-deg  grid.