The AADC (Australian Antarctic Data Centre) is in the process of converting all internally held spatial datasets to the ITRF2000 horizontal datum. This consolidated dataset consists of surveys HI623_alatB_gg, HI625_alatB_GG, HI632_alat_B_gg, HI632_alat_C_gg, LADSII_MMI20756_HSDB_T0001_SD_100029052_op, LADSII_MMI20756_HSDB_T0001_SD_100029053_op, LADSII_MMI20756_HSDB_T0001_SD_100029054_op converted to ITRF2000 horizontal datum with Z conversion values for multiple height datums. The data was provided to the AAD by Paul Digney of Jacobs consulting in March 2021. Included survey datasets: • HI623_alatB_gg • HI625_alatB_GG • HI632_alat_B_gg • HI632_alat_C_gg • LADSII_MMI20756_HSDB_T0001_SD_100029052_op • LADSII_MMI20756_HSDB_T0001_SD_100029053_op • LADSII_MMI20756_HSDB_T0001_SD_100029054_op All data are in horizontal datum ITRF2000 and have been combined into a single ESRI geodatabase feature class titled AHS_Surveys_Macca_ITRF2000. Attribute data shows quality information, conversion factors (shift in metres) for multiple datums and the MSL orthometric height: Column Name Alias Meaning Easting Easting Easting ITRF2000 Northing Northing Northing ITRF2000 LAT_to_GRS LAT_to_GRS LAT (Chart Datum) to GSR80 LAT_to_Mac LAT_to_Mac LAT to Macca MSL Z_To_GRS80 Z_To_GRS80 Height to the Ellipsoid Z_To_Macca Z_To_Macca Local MSL orthometric height Vertical_U Vertical_U How good is the Vertical Position Horizontal Horizontal How good is the Horizontal Position Uncertaint Uncertaint Uncertainty Comments Depth_Comm Depth_Comments Vertical uncertainty ranges from 0.5 to 1.2 m and horizontal uncertainty ranges from 2 to 5.5 m. Null values indicate unknown uncertainty. See the attached document ‘Metadata_Record_Macqaurie Island Final.xlsx’ for further details.

This data set is the airborne scanning LiDAR of a suite of different instruments deployed during the Sea Ice Physics and Ecosystems eXperiment (SIPEX) in 2007. Surveys have been flown over sea ice between 110-130 degrees E as part of the Australian Antarctic science project 2901. Public Summary for project 2901 This research will contribute to a large multi-disciplinary study of the physics and biology of the Antarctic sea ice zone in early Spring 2007. The physical characteristics of the sea ice will be directly measured using satellite-tracked drifting buoys, ice core analysis and drilled measurements, with detailed measurements of snow cover thickness and properties. Aircraft-based instrumentation will be used to expand our survey area beyond the ship's track and for remote sampling. The data collected will provide valuable ground-truthing for existing and future satellite missions and improve our understanding of the role of sea ice in the climate system. Project objectives: (i) to quantify the spatial variability in sea ice and snow cover properties over scales of metres to hundreds of kilometres in the region of 110-130 degrees E, in order to improve the accuracy of sea ice thickness estimates from satellite altimetry and polarimetric synthetic aperture radar (SAR) data. (ii) To determine the drift characteristics, and internal stress, of sea ice in the region 110-130 degrees E. (iii) To investigate the relationships between the physical sea ice environment and the structure of Southern Ocean ecosystems (joint with AAS Proposal 2767).

Data from ASAC project 3030. Public summary for the project: This project will measure the sea ice thickness off East Antarctica, over spatial scales up to hundreds of kilometers. Sea ice is a likely sensitive indicator of climate variations and change. No large scale sea ice thickness measurements exist in the Antarctic. An estimation of trends of change in Antarctic sea ice thickness and volume is therefore not currently possible. To address this deficiency and to provide an independent data set for the validation of models and the calibration of remote-sensing data, we will conduct high accuracy air borne laser scanner measurements in the sea ice zone off East Antarctica. More information about the project can be found in lidar.pdf (which is available with the data).