Statistical Method of Radio-Echo Sounding Temperate Mountain Glaciers and Portable Equipment for That

Abstract

Field experimental data show the possibility of using standard radio-echo sounding equipment of relatively low power to sound through a temperate mountain glacier. The main problem of sounding is the interpretation of echo signals, because they are a mixture of visually indiscernible echoes from the bed and from inhomogeneities in the body of the glacier. To get information about ice thickness and other things from such echo data, a method based on a statistical analysis of echo-signal fluctuations is proposed. As a main criterion the stability of echo-signal statistical characteristics is used.

Special portable equipment was designed based on this method. The equipment makes the interpretation of radio-echo sounding data simple. It eliminates distortions of echo signals because of receiver overloading by powerful impulses, automatically records the form and intensity of signals, makes its amplitudes proportional to reflection characteristics of the ice bed and inhomogeneities of the glacier body, and makes automatic statistical analysis. The thickness of a glacier, and the position of inhomogeneities within its body, are determined given more than ten radio-echo signal positions.

The method and the equipment have been used to determine thicknesses of Lednik Dzhankuat (Caucasus). Radio-echo sounding data have been compared with data obtained by other geophysical methods and thermal drilling. There is a good agreement (±10 m when the ice thickness is about 100 m).