All scientific data collected by the Australian Antarctic program (AAp) are eventually described in the Catalogue of Australian Antarctic and Subantarctic Metadata (CAASM). CAASM can be used to search through AAp data descriptions, and it also provides links to access publicly available datasets, which can either be immediately downloaded or obtained from the Australian Antarctic Data Centre (AADC).
These aerogeophysical data were collected as part of the ICECAP (International Collaborative Exploration of the Cryosphere through Airborne Profiling) collaboration in 2015/16 (ICP7), 2016/17 (ICP8) and 2018/19 (ICP10). These data were in part funded by the US National Science Foundation (grant PLR-1543452 to UTIG), Antarctic Gateway, ACE-CRC the G. Unger Vetlesen Foundation, and supported by the Australian Antarctic Division through project AAS-4346.
This data collection represents geolocated, time registered geophysical observations (L2 data). These data are derived from L0 and L1B data published as separate datasets. The data format are space delimited ASCII files, following the formats used for UTIG/AAD/NASA's predecessor ICECAP/OIB project at NASA's NSIDC DAAC. Fields are described in the # delimited detailed header for each granule.
Magnetics provides constraints on the depth to crystalline rock, and hence indicates the density of bathymetry
EMGEO2 geolocated magnetic anomaly profiles, 10 Hz ASCII
Gravity data is used to infer bathymetry, by looking at the density contrast between water and bathymetry
EGCMG2 geolocated free air gravity disturbance profiles; 10 Hz ASCII
Repeat track laser altimetry provides a history of thinning of outlet glaciers
ELUTP2 geolocated ice surface elevation profiles; 3.5 Hz ASCII
Ice penetrating radar provides the geometry of the ice shelves and outlet glaciers, and provides constraints on properties at the base of the ice (e.g. subglacial waters, sub ice shelf melting)
ER2HI2 geolocated ice thickness, bed and surface elevation and echo amplitude, and surface range; 4 Hz ASCII; incoherent, unmigrated processing (pik1).
We proposed to integrate aerogeophysical data collected over three critical sections of the East Antarctic grounding zone (Totten Glacier, Denman Glacier, and Cook Ice Shelf). We are motivated by their differences in recent grounding zone altimetry records and their offshore record of Cenozoic retreat.
We will assess three hypotheses to isolate the processes that drive the differences in observed grounding zone thinning:
1. Bathymetry and large-scale ocean forcing control cavity circulation;
2. ice shelf draft and basal morphology control cavity circulation;
3. Subglacial freshwater input across the grounding line controls cavity circulation.
Due to the presence of large subglacial basins under the ice sheet, the Indo-Pacific sector of the East Antarctic Ice Sheet is susceptible to ice loss through grounding line retreat. Ice shelves help prevent this retreat by exerting a buttressing effect, which is a function of the ice shelves’ thickness. However, recent airborne and satellite results have reported significant basal melting of many East Antarctic ice shelves, which decreases ice shelf thickness. As a result, lower backstress on the interior ice can potentially allow increased discharge of ice across the grounding line. For specifically these reasons, this region has been the target of ongoing United States and foreign scientific airborne and marine expeditions, as well as a major International Ocean Drilling Project effort in 2008. These studies have provided the large-scale context for the interior grounded ice and sparse continental shelf sampling which both indicate that the Indo-Pacific margin of the EAIS has advanced and retreated into the deep interior basins many times. This finding confirms the importance of better understanding of this area and its controls in order to constrain future sea level estimates.
The key outcomes of our research will be:
1. An evaluation of land ice and ocean coupling in areas of significant potential sea level contribution;
2. Relating volume changes of grounded and floating ice to regional oceanic heat transport and sub-ice shelf ocean dynamics in areas of significant potential sea level and meridional overturning circulation impacts;
3. Improved boundary conditions to evaluate mass, heat, and freshwater budgets of East Antarctica’s continental margins.
Positioning data for flights ICP7/F04, ICP7/F18 and part of ICP7/F09 was unavailable as of submission due to data corruption.
These data are publicly available for download from the provided URL.
This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/).
Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4346_EAGLE_ICECAP_LEVEL2_AEROGEOPHYSICS when using these data.