GOPH 351 Study Guide - Final Guide: International Geomagnetic Reference Field, Gravity Anomaly, Magnetization
1 Mar 2016
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Document Summary
The centripetal force tends to reduce the gravitational field. A higher order approximation to the shape of the earth. It is a model of global mean sea level that is used to measure precise surface elevations. It is a smoothly undulating shape mainly due to large scale mass concentrations. *an undulating surface equivalent to mean sea level* An anomaly field shows the difference between observed gravity field and reference gravity field. Isostasy is a theoretical gravitational equilibrium where tectonic plates float at an elevation that depends on thickness of the lithosphere and density contrast with the asthenosphere. The airy model hypothesizes that a high elevation is balanced by a thicker crust whereas the pratt model believes that higher elevations are balanced by a less dense crust instead. A higher elevation means a slightly increased radius of the earth, which decreases force of the gravitational field. It accounts for the gravitational attraction between a constant density layer and the datum.
