Influence of Hummocks on The Accuracy of GPR determination of The River Ice Cover Thickness

Summary A reliable flood forecasting system is needed, considering many climatic factors, to minimize the negative consequences of spring floods in large rivers in Siberia and the Far East. One of the important factors is the thickness of the river's continuous ice cover. For large rivers with special processes of ice formation during freeze-up, point measurements at gauging stations for areas with large hummocks become erroneous and do not reflect the real values of ice thickness over large areas. At three key sites of the gauging stations measured the thickness of river ice by GPR with a frequency of 400 MHz. The absolute values of ice thickness according to the measured data in three sites were: maximum - 2.47 meters, minimum - 0.94 meters, average - 1.5 meters. A comparative assessment of the river ice thickness obtained by GPR profiling along the width of the river and measured at the gauging stations of the Roshydromet network has been carried out. The analysis showed that in the hummock areas of the cover ice of the river, the deviations of the mean ice thickness were up to 30% of the readings of the gauging stations.