Petra Heil, Adam Steer, Rob Massom, Roger Stevens, Jennifer Hutchings and many volunteers
Sea ice is highly variable at many temporal and spatial scales. Whilst in general sea-ice physicists are looking to detect changes at the regional scale, local-scale observations are necessary to provide information on the inherent fine-scale variability in ice-thickness distribution. This data is crucial to investigate ice redistribution, to estimate the ice-mass balance, and to validate remote sensing observation techniques (including laser altimetry). Local-scale data are also used to provide verification of numerical sea-ice models. Due to the lack of remote observational techniques, there are generally few direct measurements of ice-thickness in the Antarctic sea-ice zone. During this cruise we will collect in situ data along transect lines to provide the physical characterisation of sea ice at the scale of individual ice floes.
At a typical ice station, we will make observations of sea-ice and snow thickness as well as freeboard height and the distribution of surface flooding. The snow-ice interface temperature and near-surface air temperature will also be measured using of snow probes and measurements through drill holes. These observations will be carried out every metre along two intersecting 100 – 200m transects, in order to resolve the typical length-scale in the surface variability of the ice floe.
There will also be more detailed measurements of ice and snow properties at greater spacing. We will recover full thickness sea-ice cores every 50m along these transects as well as nearby interesting ice-floe topography. The vertical ice-temperature profile will be measured immediately after recovery of each core, before the core is taken to the ship-board freezer laboratory for further analysis. In addition, snow pits will be dug and analyzed at this spatial scale.