An Overview Of Ice Profiling Using Ground Penetrating Radar (GPR)

Winter ice roads are built on water bodies in northern regions to transport goods and machinery to otherwise isolated mines and communities. Effectively monitoring ice thickness is one of the major factors that contribute to safe ice road travel. By continuously profiling the ice with Ground Penetrating Radar (GPR), thin areas can be detected by measuring the time it takes the electromagnetic pulse to travel to the ice-water contact, then converting this time to depth using the ice's velocity. Traditionally, for calibration purposes, an auger hole is drilled in the ice and its depth is used to back calculate the velocity of the ice. This method gives a fairly accurate indication of ice thickness and allows calibration at that location. However, changes in the ice's dielectric properties do exist and are primarily a function of temperature and the material’s composition – a mixture of water, air and ice. Therefore, with larger data sets, greater separations in latitude, and differences in the ice's composition, the ice’s physical properties are in constant flux. EBA Engineering Consultants Ltd. has developed a new radar system that can directly measure the ice's velocity while profiling. This paper looks at ice road data collected with traditional systems, discusses what mechanisms lay behind changing ice dielectrics and speculates that being able to measure real time variations in ice velocity may lead to a correlation in measuring ice strength.