Open AccessSurface deformation, gravity anomalies and convection
Author(s) -
McKenzie Dan
Publication year - 1977
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1977.tb01297.x
Subject(s) - geology , convection , gravity anomaly , anomaly (physics) , geophysics , wavelength , viscosity , deformation (meteorology) , mechanics , physics , optics , thermodynamics , paleontology , oceanography , oil field , condensed matter physics
Summary Long‐wavelength gravity and residual depth anomalies in the North Atlantic and Pacific Oceans resemble those obtained from numerical experiments on convective flow. To test this resemblance further the ratio of these anomalies, Z, is obtained as a function of wavelength for a variety of simple two‐dimensional convective flows. These calculations show that the ratio is insensitive to the Rayleigh number and the degree of internal heating, but is strongly affected by viscosity variations and the depth of the convecting layer. When the viscosity depends on temperature both the surface deformation and the gravity anomaly may be negative over rising regions. Comparison with available observational evidence suggests that variations of viscosity with temperature are dominant only in the vicinity of island arcs.