After allowing for the effects of sea level fluctuations, harmonic analysis of the present level of former shoreline features in southeast Fennoscandia indicates that shorter wavelength departures from equilibrium relax more rapidly than longer ones. These observations together with indicated recent secular decreases in the length of the day would seem to confirm that flow in the upper‐mantle low‐viscosity channel as a result of the Pleistocene glacial loading is the most likely source of the earth's nonhydrostatic bulge.

No abstract

In previous studies of the earth's rheology based on the times required for isostatic adjustment, the possible changes of the properties of rocks with depth have been neglected. Because recent seismological evidence points toward a crust and mantle with strongly contrasting deformational behavior, the theory of relaxation times has been formally extended to a model composed of stratified linear viscoelastic materials. Particular examples of the variation of relaxation times with wavelength for several models consisting of viscous layers, some with overlying elastic layers, are illustrated and compared with values derived from observed post‐glacial uplift of Fennoscandia.

In recent years, there has been an interest in automating the process of producing maps of the motion of ice floes from SAR images acquired a few days apart. A common approach is to correlate raw pixel values in order to find corresponding features in two images. The problem with this approach is that the search space is often prohibitive when ice floes rotate, as they frequently do. We present two algorithms for performing shape matching on ice floe boundaries in SAR images. These algorithms quickly produce a set of ice motion and rotation vectors that can be used to guide a pixel value correlator. The algorithms match a shape descriptor known as the $-s curve. The first algorithm uses normalized correlation to match the $-s curves, while the second uses dynamic programming to compute a n elastic match that better accommodates ice floe deformation.

To evaluate the magnitude of radiative thermal conductivity in planetary interiors, it is necessary to measure the high‐temperature absorption coefficient and refractive index of relevant minerals in the appropriate spectral region. We have made near‐infrared measurements on samples of olivine, diopside, and oligoclase at temperatures up to 1723°K. The results of our studies show continuous broadening of the vibrational and electronic bands involved, with a consequent substantial increase in mineral opacity in a spectral region that is effectively a window for room‐temperature samples. This opacity significantly decreases the magnitude of radiative thermal conductivity from what one would predict from room‐temperature spectra.