Earth`s Cryosphere», 2018, Vol. XXII, № 3, p. 16-23
RESULTS OF GROUND-PENETRATING RADAR INVESTIGATIONS ON THE NELLA FJORD SEA ICE (PROGRESS STATION AREA, EAST ANTARCTICA) IN THE 2016/17 AUSTRAL SUMMER FIELD SEASON
S.V. Popov1, V.L. Kuznetsov2, S.S. Pryakhin2, M.P. Kashkevich3
1Polar Marine Geosurvey Expedition (PMGE), 24, Pobeda str., Lomonosov, St. Petersburg, 198412, Russia; spopov67@yandex.ru
2Arctic and Antarctic Research Institute, 38, Bering str., St. Petersburg, 199397, Russia
3Saint-Petersburg University, 7-9, Universitetskaya emb., St. Petersburg, 199034, Russia
The paper presents the main results of the field investigations using multi-frequency (150 MHz, 270 MHz, 400 MHz and 900 MHz) ground-penetrating radar profiling and georadar sensing by the common depth point method. The investigations have been carried out on the fast sea ice of Nella Fjord (Eastern Antarctica) during the 2016/17 austral summer field season. The studies have included seawater salinity measurements. The sounding of sea ice with thickness of about 1 m thick have proved to be most effective at the radar frequencies which correspond to the wavelengths in a meter range. Besides the intensive reflections from the lower edge of sea ice, the ground-penetrating radar data have revealed a boundary between fresh- and saltwaters whose position has been corroborated by the salinity measurements. The ground-penetrating radar technique in CDP mode has served as a basis for the subsurface velocity model showing that the effective dielectric constant for sea ice equals 10, which is accounted for intense melting of sea ice and its saturation with fresh water. The value of effective permittivity the fresh water layer is found to be 75, which may have been prompted by roughness of the lower edge surface of sea ice.
East Antarctica, Progress Station, ground-penetrating radar sounding, sea ice, common depth point, seawater salinity