Disturbance Vector in Space from Surface Gravity Anomalies Using Complementary Models.
Abstract
The modeling of the external disturbance vector of the earth from surface gravity anomaly data is discussed. The low frequency features of the signal are represented in spherical harmonic series. The recovery of the coefficients of the series from the given gravity anomalies is discussed focusing on the use of analytical continuation and ellipsoidal corrections to account for the earth's topography and ellipticity. The spectrum and data response of the spatial disturbance vector are studied to aid the design of models and experiments. The local models studied to complement the globally valid spherical harmonic model are the residual topographic model (RTM); the classical integral model; three versions of the Dirac approach to collocation; and two versions of the least squares collocation (l.s.c.) approach. Results indicate that the RTM itself should be used to model the high frequency signal variations whenever detailed (e.g., 1km x 1km) height data is available. The residual signal not already modeled by the RTM and spherical harmonic model can in most cases be accurately modeled by the integral model with mean topography accounted for. For high accuracies in mountainous areas, however, a collocation model should be used to account for the full variations of the topography, not just mean topography. Matrix conditioning problems with the 1.s.c. approach support preference to the Dirac systems for rigorous treatment of the topography at detailed (5' x 5') resolutions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1985
- Accession Number
- ADA166730
Entities
People
- Jaime Y. Cruz
Organizations
- Ohio State University