Determination of ice cover thickness using compression standing waves

Abstract

Information about the ice cover thickness is necessary for solving many practical problem, from ensuring the safe movement of people and transport over frozen water bodies to assessing the reserves of glacial water. The purpose of this study is to assess the possibilities of using the passive standing wave method to determine the thickness of the ice layer on the water surface or frozen ground. The method is based on the generation of the compression standing waves family from acoustic noise in the ice layer. With regards to the problem under consideration, this phenomenon is confirmed by the results of laboratory experiments and numerical simulations for an ice layer in contact with water and frozen saturated sand. It is shown that the accumulation of amplitude spectra of noise records made on the surface of the ice layer makes it possible to determine the frequencies of several lower modes formed in the layer of compression standing waves. At a known velocity of longitudinal waves in ice, these frequencies can be used to estimate both the thickness of the ice layer and the type of underlying medium (water or frozen ground). The method was tested in natural conditions on two reservoirs, a small river and in the coastal part of the reservoir.