Institute of Geophysics, University of Tehran, P.O. Box 14155-6466, Tehran, Iran And Center of Excellence in Surveying Engineering and Disaster Monitoring (CESEDM)
One-dimensional fast Fourier transform (1D FFT) is used to solve the ellipsoidal Stokes integral (Martinec and Grafarend, 1997) in an ellipsoidal cap around the computational point (near-zone contribution) numerically.
For the far-zone contribution the spherical harmonic expansion can be applied. The geoidal height computation through direct numerical solution of the integral and 1D FFT will be compared for an area in Canada. The comparison shows relatively a great difference due to the application of FFT to the original ellipsoidal Stokes integral.