Recent changes in the polar cryosphere have been dramatic, and include the well known reduction of the Arctic sea-ice cover during the annual ice mimimum (in late boreal summer). Furthermore the projected climate change (e.g., AMAP ) is likely to result in a volume loss of both Arctic and Antarctic sea-ice. Sea-ice volume can be quantified as the product of sea-ice covered area and thickness. In the Arctic, thinning of the sea ice and a reduction in its summer extent and thus a reduction in sea-ice volume have been well documented [Perovich, 2011; Kwok et al., 2009] and sustained themselves up to 2016. In the Antarctic, however and albeit with strong regional variability, the overall sea-ice area has expanded slightly over the past few decade, just to collapse in 2016, when the Antarctic winter sea-ice extent was well below the 1980 – 2010 mean [NOAA, 2017].
Project objectives & goals
The primary objective of this proposal is to identify and proto-type a processing chain to derive Antarctic sea-ice thickness from a range of remotely-sensed observations, in order to understan its spatial-temporal characteristics in response to change and variability in external forcing. While areal extent of sea ice is routinely monitored by satellite passive microwave sensors, deriving sea-ice (or snow) thickness from remote observation presents a matter of urgency in informing sea ice and climate research. Both sea-ice areal extent and thickness exhibit high spatio-temporal variability, as they are affected by complex interactions involving dynamic and thermodynamic processes across a wide range of spatial-temporal scales.
In order to address this critical knowledge gap, the proposed project will address the following objectives:
To compile an updated summary of current and near-term satellite-derived sea-ice products;
to investigate the available products with a view to deriving the mean seasonal sea-ice thickness distribution from independent data obtained from satellite-based and aerial (Operation IceBridge) altimeters;
to evaluate the derived sea-ice and snow thickness data using independent (remotely-sensed) data sets;
to conduct regional case studies to explore processes, including ice kinematics, that affect the thickness distribution of polar sea ice.
To achieve these, we propose to bring together a group of experts in satellite-data interpretation and harvesting as well as numerical modellers, to discuss current topical issues with the aim to populate key parameters (including the snow- and sea-ice thickness distribution) in the data-sparse polar regions. Our investigation will take up data products from standard data archives, such as NSIDC or ESA’s Copernicus archive, and will be supplemented with dedicated data (ie. TerraSAR-X from grants) and aerial data from Operation IceBridge.
AMAP 2009 Update on Selected Climate Issues of Concern, Arctic Monitoring and Assessment Programme, Oslo, v, 15pp, ISBN 978-82-7971-049-3, 2009.
Kwok, R., Cunningham, G.F., Wensnahan, M., Rigor, I., Zwally, H.J. and Yi, D. Thinning and volume loss of the Arctic Ocean sea ice cover: 2003-2008, Journal of Geophysical Research-Oceans, 114, pC07005, 2009.
NOAA National Centers for Environmental Information, State of the Climate: Global Snow and Ice for Annual 2016, http://www.ncdc.noaa.gov/sotc/global-snow/201613, 2017.
Perovich, D.K., The changing Arctic sea ice cover, Oceanography, 24(3), 162 – 173, doi: 10.5670/oceanog.2011.68, 2011.