Self-Attraction and Loading of Oceanic Masses

When attempting to simulate sea-level variations precisely, the gravitational potential of the moving water masses themselves and their capability of modifying the Earth’s shape have to be considered. Self-attraction and loading (SAL) describes said effects. We describe SAL theoretically, deriving equations that allow to compute SAL either with spherical harmonic functions or with a convolution integral, and show how the equations can be modified to reduce computational demands of the calculation. Key questions of past and ongoing research on the topic include a quantification of SAL at periods from days to years and generated by different processes, the possibility of dynamical feedbacks, and the question of how SAL can be adequately represented in various modeling applications. Gravitation being a body force of infinite range, investigations of SAL include a wide range of processes connected to mass redistribution. For instance, this includes the fast tidal variability, but also atmospherically induced ocean dynamics, or mass redistribution on land and in the atmosphere. Future research is expected to be focused on tidal applications and to consider SAL on longer time scales as an equilibrium response.