Abstract:
This data set decribes surface and volume properties of snow and ice to validate radar satellite measurements. Ground penetrating radar (GPR) at 500 and 1000GHz provides information on snow layers and thickness near the surface at two sites on the McMurdo Ice Shelf, one site at Ross Island, and on the landfast and new sea ice in McMurdo Sound. A 50MHz antenna is used to measure total ice thickness
... and the thickness of the ice above the saline layer underneath the ice shelf. Snow density and morphology is measured in snow pits using standard glaciological methods and an infrared camera, as well as an ice corer for depths down to about 8m. Snow stakes were used to measure the annual accumulation on land ice over a one year period. A dust layer is used to quantify the average accumulation over a 5 year period. Stake and GPR measurements suggest a high temporal and spatial variabilty in snow accumulation near Ross Island. A laser ranger on the skidoo and a small unmanned aircraft are used to determine the surface roughness of snow on land ice. For sea ice, the GPR system is used on one north south and two east-west transects to measure snow thickness on ice. Ice drilling is used to determine total sea ice thickness along the transects. A helicopter EM bird is used to measure a grid of sea ice and ice shelf thickness across the McMurdo Sound. Ground measurements validate the performance of the HEM bird in the presence of platelet ice.
In 2011 more in-depth research was conducted into sea ice thickness. The subice platelet layer thickness under sea ice was measured in regular intervals at two North-South oriented profiles and four east-west oriented profiles. Holes were drilled at regular intervals into sea ice at measurement sites about 5 km apart. At these holes sea ice thickness and snow depth on top of the sea ice was measured. In between the sites, sea ice thickness was measured using an electromagnetic induction device, and snow on sea ice was measured using a ground penetrating radar system. Ocean temperature and salinity was measured through holes in the sea ice along the ice edge of the McMurdo Ice Shelf within 3 km of the ice shelf front. The response of the sea ice to tidal height was measured at three locations using GPS Stations. At these locations samples of sea ice were taken for geophysical, oceanographic and biological analysis. Water samples were also taken.
Sea ice thickness (surface elevation and draft of sea ice) and surface reflectance was measured along ten North-South oriented profiles and eight east-west oriented profiles. This was performed by the HEM bird and the ground measurements validate these results.