Gravity Field: Marine Geosciences

Definition

The gravity field in marine geosciences is the gravitational force that the Earth’s mass exerts on objects on or near its surface.

Introduction

The basic principle for the Earth’s gravity field in classical mechanics is Newton’s law of universal gravitation. It states that every massive body exerts an attractive force on all other massive objects. The force is proportional to the product of the bodies’ masses and inversely proportional to the square of the distance between them. For extended bodies like the Earth, their mass can be assumed to be concentrated as a point mass in their center (strictly this is only true for spheres with a symmetrical mass distribution). In geophysics, Newton’s law is used in the form

$$ \underset{\bar{\mkern6mu}}{K}=G\frac{mM}{r^2}\underset{\bar{\mkern6mu}}{r^0} $$

where $G={6.672}^{\ast }{10}^{-11}{\mathrm{Nm}}^2{\mathrm{kg}}^{-2}$ is the gravitational constant, m the mass of a body on or near Earth’s surface, M Earth’s mass, rthe...