Ice shelf density reconstructed from optical televiewer borehole logging

摘要

Optical televiewer luminosity logs are compared with densities measured gravimetrically on 520 snow, firn, and ice samples from two locations of similar annual temperature (~ -14°C) and contrasting accumulation rates (0.23 and 0.43m water equivalent per year) on the Roi Baudouin Ice Shelf, Antarctica. At the scale of ≥10~(-1) m, an inverse exponential relationship (R~2 = 0.96) is recorded between density and luminosity, indicating (i) that optical televiewing luminosity provides an effective proxy for density at such ice shelves and (ii) that densities may be reconstructed from boreholes drilled elsewhere by hot water without the need for core material. Our analysis also suggests that this relationship may hold for newly formed ice as well as for snow and firn. At the scale of ≤10~(-1) m, both luminosity and density show similar patterns, but precise correlation is confounded by detailed differences between the two records. Citation: Hubbard, B., J.-L. Tison, M. Philippe, B. Heene, F. Pattyn, T. Malone, and J. Freitag (2013), Ice shelf density reconstructed from optical televiewer borehole logging, Geophys. Res. Lett., 40, 5882–5887, doi:10.1002/2013GL058023.