Identification of River Ice Cover Structure by Ground Penetrating Radar Data

Abstract

To predict and prevent emergencies resulting from dangerous ice phenomena (ice blocks, insufficient ice cover capacity, ice jams), information on the structure and thickness of river ice cover is required. Currently, the ground penetrating radar (GPR) method is used for operative research of ice cover condition on long river sections during the freeze-up period. The article presents materials of interpretation of the GPR studies of the ice cover structure of the Lena River in the vicinity of Yakutsk. Analysis of the parameters of radargram wave patterns (fragmentation, subhorizontal, broken, continuity of reflected wave events, amplitude and phase of reflected waves) allowed us to determine the main types of ice structure, such as monolithic ice, fast ice and hummocky ice. Statistical evaluation of the variation of reflected wave amplitudes from the ice cover allowed us to reveal the nature of the homogeneity of the set of amplitude values depending on the ice structure. As a result, an algorithm for processing and interpreting large volumes of airborne GPR data was developed, making it possible to make a reliable assessment of the thickness and structure of river ice cover, as well as to map the spatial distribution of its heterogeneities in the river channel. The information obtained about the state of river ice cover can be used for engineering-geophysical surveys, operation of ice crossings, substantiation of decisions on the application of preventive measures to destroy thick ice in the jam-prone river sections in order to safely pass the spring flood waters.