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ICE THICKNESS

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  • AM01 borehole drilled January 2002. Data collected in series of files over a period of 2 days after completion of borehole. Consult Readme file for detail of data files and formats.

  • A Lambert Glacier - Amery Ice Shelf series of airborne (Squirrel helicopter and Twin Otter fixed wing) RES and surface elevation profiles were conducted over two summer seasons; 1988/89 and 1989/90. Altogether nearly 10,000 km of various flight paths were undertaken, operating out of Mawson (67.60 S, 62.88 E), Davis (68.58 S, 77.97 E), Dovers (70.22 S, 65.87 E) or Beaver Lake (70.80 S, 68.18 E). More information can be found at the BEDMAP website. The fields in this dataset are: mission_id (unique mission identifier) latitude (decimal degrees) longitude (decimal degrees) ice_thickness (m) surface_elevation (m) water_column_thickness (m) bed_elevation (m)

  • Ice shelf surface elevation data from an oversnow ground-based traverse along the centre of the Amery Ice Shelf from A509 (69.06 S, 72.15 E) to T4 (71.22 S, 69.48 E), including two transverse arms; between G1 (69.49 S, 71.72 E) and A119 (69.81 S, 73.28 E); and between T3 (70.79 S, 68.89 E) and T2 (71.00 S, 70.75 E) during the 1968 spring-summer season. More information can be found at the BEDMAP website. The fields in this dataset are: Mission ID Latitude Longitude Ice Thickness Surface Elevation Water Column Thickness Bed Elevation

  • AM02 borehole drilled December 2000. Profiling measurements conducted over a period of one week. Long term monitoring instruments installed 2001-01-06. Consult Readme file for detail of data files and formats.

  • AM01 borehole drilled mid-January 2002. Profiling measurements conducted over a period of one week. Long term monitoring instruments installed 2002-01-16. AM01b borehole drilled mid-December 2003. Video recording of borehole walls and sea floor benthos. Sediment sample collected from sea floor.

  • Preliminary Metadata record for data expected from ASAC Project 1126 See the link below for public details on this project. ---- Public Summary from Project ---- Previous work on anti-freeze proteins (AFPs) in bacteria isolated from saline lakes in the Vestfold Hills, has shown that only around 10% of isolates possessed AFP activity. This suggests that the majority of bacteria may be using other mechanisms to avoid freezing or possibly are non-functional at sub-zero temperatures. We propose building on our previous work to ascertain if AFP occurrence is characteristic of particular taxonomic groups, or whether its evolution is random among different species. The fields in this dataset are: Lake Date Air Temperature Ice Thickness Sample Type Depth Height of ice core sample from ice/water interface Thickness of Ice core sample Salinity Water Temperature Nitrate Nitrite Ammonia Phosphate Bacteria Flagellates Chlorophyll DOC - Dissolved Organic Carbon COV of DOC - Coefficient of Variance

  • AM01b borehole drilled mid-December 2003. Profiling measurements conducted over a period of a few days. Video recording of borehole walls and sea floor benthos. Sediment sample collected from sea floor. No long term monitoring instruments installed. AM01b borehole was drilled within a few hundred metres of where the ice shelf had carried the original AM01 borehole to, in the intervening 2 years. As the AM01 borehole had a mooring suite of instruments, none were emplaced in the AM01b borehole.

  • AM01b borehole drilled mid-December 2003. Profiling measurements conducted over a period of a few days. Video recording of borehole walls and sea floor benthos. Sediment sample collected from sea floor. No long term monitoring instruments installed. AM01b borehole was drilled within a few hundred metres of where the ice shelf had carried the original AM01 borehole to, in the intervening 2 years. As the AM01 borehole had a mooring suite of instruments, none were emplaced in the AM01b borehole. There are several video files attached to this metadata record, and further details about them are provided in the accompanying readme document. The data file contains downcam video, sidecam video and miscellaneous video.

  • Metadata record for data from ASAC Project 1342 See the link below for public details on this project. ---- Public Summary from Project ---- This project involves field trialling of software written as part of ASAC project 1212 (2000-2001) to determine sea-ice thickness in real-time from ship-borne electromagnetic induction measurements. Computer simulation of ship- and helicopter-borne electromagnetic induction measurements over realistic sea-ice structures will also be performed in order to assess the suitability and cost-effectiveness of helicopter-mounted systems for future Antarctic sea-ice thickness measurements. Equipment used in this study were the IBEO PS100 infrared laser altimeter and the Geonics EM31 geophysical electromagnetic induction device. The fields in this dataset are: DAY is Julian day TIME is in seconds after midnight (UTC). LASER is the laser altitude above the snow/ice (metres). A zero reading indicates no return (open water). PITCH is pitch of the system in degrees. ROLL is roll of the system in degrees. COND-A is analogue conductivity from the EM31 (not used). PHASE-A is analogue in-phase response from the EM31 (not used). COND is the estimated depth to seawater (metres) from the EM31-ICE processing module. PHASE is the EM31 in-phase response (expressed as parts per thousand of the primary field). A value of 9.99 indicates the magnetic field was too large to be recorded. SITE LATITUDE LONGITUDE SNOW THICKNESS ICE THICKNESS FREEBOARD a is the electrode spacing. R is the measured resistance. Rho is the apparent conductivity (not true conductivity) = 2 aR. CONDUCTIVITY = 1/Rho.

  • ---- Public Summary from Project ---- Most of the snow falling on inland Antarctica drains via large ice streams and floating ice shelves to the sea where it lost by iceberg calving or as melt beneath the shelves. Ocean interaction beneath the shelves is complicated, and regions of basal refreezing as well as melt occur. These processes are important not only because they are a major component of the Antarctic mass budget, but because they also modify the characteristics of the ocean, influencing the formation of Antarctic Bottom Water which plays a major role in the global ocean circulation. The processes are sensitive to climate change, and shifts in ocean temperature or circulation near Antarctica could lead to the disappearance of all Antarctic ice shelves. The Amery Ice Shelf is the major embayed shelf in East Antarctica, and the subject of considerable previous ANARE investigation. Ocean interaction processes occurring beneath the shelf are only poorly understood, and this project will directly measure water characteristics and circulation in the cavity underneath the ice shelf, and the rates of melt and freezing on the bottom of the shelf. These measurements will be made through a number of access holes melted through the shelf. The project is closely linked with other projects investigating the circulation and interactions in the open ocean to the north of the shelf, and studies of the ice shelf flow and mass budget. There will be child records for each of the following data sets: AM01 and AM01 b boreholes * CTD profiles through water column * CTD annual records at selected depths * Ocean current profiles through water column * Temperature measurements through ice shelf and across ice-water interface * Small ice core samples * 0.5 m sea floor sediment core * Video footage of borehole walls (including marine ice) and sea floor benthos * GPS records of surface tidal motion * Video AM02 borehole * CTD profiles through water column * CTD annual records at selected depths * Borehole diameter caliper profiles * Temperature measurements through ice shelf and across ice-water interface * 1.5 m sea floor sediment core * GPS records (surface elevation, ice motion) AM03 borehole * Aquadopp current meter data * Brancker thermistor data * Caliper data * FSI-CTD profile data * Drilling parameters data * Seabird MicroCAT CTD moorings at three depths in ocean cavity beneath the shelf * Video AM04 borehole * Aquadopp current meter data * Brancker thermistor data * Caliper data * FSI-CTD profile data * Drilling parameters data * Seabird MicroCAT CTD moorings at three depths in ocean cavity beneath the shelf * Video AM05 borehole * Aquadopp current meter data * Caliper data * FSI-CTD profile data * Drilling parameters data * Seabird MicroCAT CTD moorings in ocean cavity beneath the shelf AM06 borehole * Aquadopp current meter data * Caliper data * FSI-CTD profile data * Drilling parameters data * Seabird MicroCAT CTD moorings in ocean cavity beneath the shelf Taken from the 2008-2009 Progress Report: Progress Against Objectives: The work undertaken in the past 12 months has continued to relate chiefly to the first of our objectives - "quantify the characteristics and circulation of ocean water in the cavity beneath the Amery Ice Shelf". Data from the AMISOR project have provided the first record of a seasonal cycle of ice shelf-ocean interaction. After recovering the 2008 data we now have near-continuous oceanographic data from beneath the Amery at 3 different depths for 6, 6, 3, and 3 years from 4 different sites. Note that the instruments at AM01 and AM02 (6 annual cycles of data each) are no longer recording due to expiration of the onboard batteries (3-5 years expected life cycle). This allows us to investigate the "real" 3-D, seasonally varying, circulation and melt/freezing cycle beneath an ice shelf - rather than the steady state, simplified "2-D ice pump circulation" that has mostly been assumed previously. As much as 80% of the continental ice that flows into the Amery Ice Shelf from the Lambert Glacier basin is lost as basal melt melt beneath the southern part of the shelf, but a considerable amount of ice is also frozen onto the base in the north-western part of the shelf. These processes of melt and refreezing are due to a pattern of water circulation beneath the ice shelf which is driven by sea ice formation outside the front of the shelf. Our multi-year data from 4 sites beneath the Amery ice shelf show that there is a very strong seasonal cycle in the characteristics of the ocean water beneath the shelf, and strong interseasonal variability in this. The seasonal cycle is driven mostly by the seasonal cycle of sea ice formation and decay in Prydz Bay, and interseasonal variations are due to differences in the general ocean circulation, and in particular the upwelling of Circumpolar Deep Water onto the continental shelf in Prydz Bay. The melt and freeze processes beneath the ice shelf, also themselves modify the water characteristics. Taken from the 2009-2010 Progress Report: The AMISOR project drilled two new 600 m deep boreholes on the Amery Ice Shelf in 2009-10: the first on the marine ice flowline to enhance understanding of the re-freezing process beneath the shelf; and the second in a region of known interest with respect to circulation patterns in the ocean cavity below the shelf. Instrument deployments at both sites should provide valuable annual cycle data over the next 4-5 years.