New ground penetrating radar system for quantitative characterization of snow and sea ice

We examine the use of ground penetrating radar (GPR) to simultaneously estimate snow and ice thickness. Since velocity is essential for depth inversion, we developed an automatic common mid-point (CMP) measurement system, which can work in an ultra-wide band. Envelope velocity spectrum, robust in reflection identification, is used to estimate the dielectric permittivity and layer thickness from CMP datasets. We tested our system on a 50-m-long test line on a brackish lagoon, i.e. Lake Saroma, in Hokkaido, Japan, in February 2012. Compared with the ground truth, the snow and ice thickness estimations possess a good accuracy, with a respective mean absolute error of about 2 cm (12%) and less than 2 cm (4%), which verifies the accuracy of their dielectric permittivity estimation. Then the estimated two-layer velocity model obtained by interpolation was used to continuously estimate the snow and ice thickness from the common-offset (CO) GPR profile acquired by a commercial GPR system. The mean absolute errors of snow and ice thickness estimated from the CO profile are respectively, about 3 cm (18%) and less than 6 cm (14%). Our system and method appear capable of accurately measuring the dielectric permittivity and thickness of other layered media.