Note - these data should be used with caution. The chief investigator for the dataset has indicated that a better quality dataset exists, but the AADC have been unable to attain it for archive. In addition to snow pits dug by other groups, several snow pits were dug at IMB/AWS deployment sites and at snow mast sites. Dates, locations, personnel, and purpose are listed in Table 1. Many of the data files include the raw weight measurements including the mass of the snow density shovel along with the snow. This needs to be corrected using the snow density shovel weight appropriate to each pit. Table 1 Snow Pits (comma separated) Date,Location,Personnel,Comments 2012-10-04,Floe 3 radiometer site,Katie,Full-depth snow density profile for evaluation of SMP data 2012-10-08,Floe 4 drift mast,Katie,Full-depth snow density profile for evaluation of SMP data 2012-10-14,Floe 6 buoy 1,Katie,Full-depth snow density profile for evaluation of SAMS WHOI-3 data 2012-10-14,Floe 6 buoy 2,Katie,Full-depth snow density profile for evaluation of SAMS WHOI-5 data 2012-10-20,Floe 7 drift mast,Ted,Snow pit to characterise snow at ice station 7 drift mast site 2012-10-23,Floe 7 drift mast,Katie,Full-depth snow density profile for evaluation of SMP data 2012-10-28,Helicopter buoy install,Petra,Snow pit for evaluation of SAMS- WHOI-4 buoy data 2012-10-29,Helicopter buoy install,Petra,Snow pit for evaluation of SAMS- TASI2-1 buoy data 2012-11-01,Floe 8,Ted,Snow pit for evaluation of WHOI-2 buoy data 2012-11-04,Floe 6 buoy re-install,Ted,Snow pit for evaluation of WHOI-6 buoy data

This dataset contains in situ measurements of ice thickness, snow thickness, and freeboard along transects on the ice-station floes from the SIPEX2012. Ice cores were collected and snow pits were measured at the 0m, 50m and 100m mark along each transect, where possible. Ice temperature measurements are taken in the field as soon as the ice core sections have been recovered from the core hole. Additionally, ice cores were taken for density analysis at a few of the ice-core sites for independent verification of ice density. In addition, electromagnetic [EM] induction measurements of total ice and snow thickness were conducted along the transect where possible. Ice core were transferred -20oC freezer for thin-section analysis for sea-ice stratigraphy and crystallography. The cores are then cut up into suitable short sections, generally about 5cm long, to be melted for analysis of salinity and stable oxygen isotopes. The latter will occur after the end of this cruise. There is a data file for each ice station, containing a spreadsheet with the data. The spreadsheet contains information about how to interpret the data. Also included are the scanned field notes containing the hand-written (raw) data collected in the field. Among many, many volunteers, whose help is gratefully acknowledged here, the following persons were involved in data collection along the transect: Mr Olivier Lecomte, Univ Catholique, Louvain-la-Neuve, Belgium, Member of observation team, olivier.lecomte@uclouvain.be Dr T. Toyota, Inst Low Temp Science, Japan, Member of observation team, toyota@lowtem.hokudai.ac.jp Dr A. Giles, ACE CRC, Member of observation team, barry.giles@utas.edu.au Dr T. Tamura, NIPR, Japan, Member of EM observation team; tamura.takeshi@nipr.ac.jp Mr K. Nakata, EES, Japan, Member of EM observation team; kazuki-nakata@ees.hokudai.ac.jp Data were collected on the following dates: Ice Station 2: 27 - 28 September 2012 Ice Station 3: 03 - 04 October 2012 Ice Station 4: 06 - 08 October 2012 Ice Station 6: 13 - 14 October 2012 Ice Station 7: 19 - 23 October 2012 Ice Station 8: 29 October - 04 November 2012

This dataset contains the data collected during the RAPPLS (Radar, Aerial Photography, Pyrometer, and Laser Scanning system) flights that were undertaken as a part of the SIPEX II (Sea Ice Physics and Ecosystems Experiment II) Antarctic marine science voyage in September-November 2012. The RAPPLS project involved designing and using a system using a helicopter with mounted sensors to record data while flying over sea ice. The RAPPLS helicopter is an Aerospaciale AS 350 BA "Squirrel" helicopter with a range of scientific equipment mounted to it. These are generally imaging instruments that are used to derive snow and ice properties, such as roughness, surface elevation and skin temperature. The following is a list of instruments used and parameters measured: - 2-8 GHz frequency modulated continuous wave radar, measuring impedance differences between snow and sea ice; - Hasselblad H3D II 50 camera, taking aerial photographs at about 13 cm resolution every 3-5 seconds - Heitronics KT 19 pyranometer, measuring skin surface temperature - Riegl LMS Q240i-60 scanning LiDAR, measuring surface elevation of sea ice above sea level All data are geo-located with a combined inertial navigation and global positioning system, OxTS RT-4003. See Australian Antarctic Division Science Technical Support Project 07006 for detailed Engineering documents. Detailed flight information for each flight is available from WORD documents for each survey. Contained in this dataset are the following files: - A MS Word log file for all flights; - A QGIS map file showing all flights; - A folder for each flight containing the following (named - Date - Fxx - Mission: - A Microsoft Word document explaining the flight intentions, issues, and outcomes (flight log); - A folder of the photos taken by the Hasselblad camera; - A folder of raw and processed INS data: - RD files, which are raw INS and can be opened RT_PostProcess software; - PNG Files showing flight track, created with RT_View software based on NCOM files resulting from RT_PostProcess; - A folder with log files for Errors, Events, LaserScanner, Pyrometer, and INS. This folder also includes Q24 file of raw laser scanner data (purpose written software to analyse the data is available with the 2008 data set); - A folder with time synchronisation log file.

Motivation: One of the characteristics of this voyage is that we have long ice stations which last for a few days. Taking this opportunity, we decided to examine the diurnal change of snow properties at the fixed snow pit site. Since this measurement was not included in the original plan, Time interval was a bit variable from 3 hours to 5 hours depending on the progress of the other work. Observation items: Snow thickness, Temperature profile (every 3 cm), Grain size, Grain shape, Snow density, Hardness, Salinity Instruments: Folding scales, Spatula, Thermometer, Snow sampler, Magnifying glass, Salinometer Information pertaining to the dataset: Time - recorded in local time Hs - snow depth in cm Cloud measurements - oktas Water level - distance between snow surface and surface seawater in cm Depth - depth of the individual layer referenced to snow/ice interface (upper column) or snow surface (lower column) in cm Ta - air temperature in degrees celsius DH, FC, PP, DF, RG stand for Depth hoar, Faceted crystals, Precipitation particles, Decomposing and fragemented precipitation particles, Rounded grains - according to "The International Classification for Seasonal Snow on the Ground" (Colbeck et al., 1990). Weight - g Mid-depth - cm

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). Taken from the abstract of the PhD thesis accompanying the dataset: Antarctic sea ice and its snow cover are integral components of the global climate system, yet many aspects of their vertical dimensions are poorly understood, making their representation in global climate models poor. Remote sensing is the key to monitoring the dynamic nature of sea ice and its snow cover. Reliable and accurate snow thickness data from an airborne platform is currently a highly sought after data product. Remotely sensed snow thickness measurements can provide an indication of precipitation levels. These are predicted to increase with effects of climate change, and are difficult to measure as snow fall is frequently lost to wind-blown redistribution, sublimation and snow-ice formation. Additionally, accurate regional scale snow thickness data will increase the accuracy of sea ice thickness retrieval from satellite altimeter freeboard estimates. Airborne snow-depth investigation techniques are one method for providing regional estimation of these parameters. The airborne datasets are better suited to validating satellite algorithms, and are themselves easier to validate with in-situ measurement. The development and practicality of measuring snow thickness over sea ice in Antarctica using a helicopter-borne radar forms the subject of this thesis. The radar design, a 2-8 GHz Frequency Modulated Continuous Wave Radar, is a product of collaboration and the expertise at the Centre for Remote Sensing of Ice Sheets, Kansas University. This thesis presents a review of the theoretical basis of the interactions of electromagnetic waves with the snow and sea ice. The dominant general physical parameters pertinent to electromagnetic sensing are presented, and the necessary conditions for unambiguous identification of the air/snow and snow/ice interfaces by the radar are derived. It is found that the roughness's of the snow and ice surfaces are dominant determinants in the effectiveness of layer identification in this radar. Motivated by these results, the minimum sensitivity requirements for the radar are presented. Experiments with the radar mounted on a sled confirm that the radar is capable of unambiguously detecting snow thickness. Helicopter-borne experiments conducted during two voyages into the East Antarctic sea-ice zone show however, that the airborne data are highly affected by sweep frequency non-linearities, making identification of snow thickness difficult. A model for the source of these non-linearities in the radar is developed and verified, motivating the derivation of an error correcting algorithm. Application of the algorithm to the airborne data demonstrates that the radar is indeed receiving reflections from the air/snow and snow/ice interfaces. Consequently, this thesis presents the first in-situ validated snow thickness estimates over sea ice in Antarctica derived from a Frequency Modulated Continuous Wave radar on a helicopter-borne platform. Additionally, the ability of the radar to independently identify the air/snow and snow/ice interfaces allows for a relative estimate of roughness of the sea ice to be derived. This parameter is a critical component necessary for assessing the integrity of satellite snow-depth retrieval algorithms such as those using the data product provided by the Advanced Microwave Scanning Radiometer - Earth Observing System sensor on board NASA's Aqua satellite. This thesis provides a description, solution or mitigation of the many difficulties of operating a radar from a helicopter-borne platform, as well as tackling the difficulties presented in the study of heterogeneous media such as sea ice and its snow cover. In the future the accuracy of the snow-depth retrieval results can be increased as technical difficulties are overcome, and at the same time the radar architecture simplified. However, further validation studies are suggested to better understand the effect of heterogeneous nature of sea ice and its snow cover on the radar signature. RAASTI = Radar For Antarctic Snow Thickness Investigation

ASPeCt is an expert group on multi-disciplinary Antarctic sea ice zone research within the SCAR Physical Sciences program. Established in 1996, ASPeCt has the key objective of improving our understanding of the Antarctic sea ice zone through focussed and ongoing field programs, remote sensing and numerical modelling. The program is designed to complement, and contribute to, other international science programs in Antarctica as well as existing and proposed research programs within national Antarctic programs. ASPeCt also includes a component of data rescue of valuable historical sea ice zone information. The overall aim of ASPeCt is to understand and model the role of Antarctic sea ice in the coupled atmosphere-ice-ocean system. This requires an understanding of key processes, and the determination of physical, chemical, and biological properties of the sea ice zone. These are addressed by objectives which are: 1) To establish the distribution of the basic physical properties of sea ice that are important to air-sea interaction and to biological processes within the Antarctic sea-ice zone (ice and snow cover thickness distributions; structural, chemical and thermal properties of the snow and ice; upper ocean hydrography; floe size and lead distribution). These data are required to derive forcing and validation fields for climate models and to determine factors controlling the biology and ecology of the sea ice-associated biota. 2) To understand the key sea-ice zone processes necessary for improved parameterization of these processes in coupled models. These ASPeCt measurements were taken onboard the Aurora Australis during the SIPEX voyage in the 2007-2008 summer season.

This dataset contains routine measurements of snow and ice thickness, and snow-ice interface temperature, at 1m intervals along standard transects; snow property characterisation in snow pits measured at 0m, 50m and 100m along the transects; and sea ice cores acquired at various locations both along the transects and elsewhere on ice station floes during the 2012 SIPEX 2 marine science voyage. Ice temperature information is acquired from the cores, which are taken on-board for further analysis. The latter includes thin-section analysis of sea-ice stratigraphy and crystallography at -20C within the freezer lab on-board the ship. The cores are then cut up into 5cm sections and melted for analysis of salinity and stable oxygen isotopes. Observation items: Snow: - Thickness - Temperature profile (every 3 cm) - Snow-ice interface temperature at 1m intervals along the 100m transects - Grain size - Grain shape - Density - Hardness - Salinity - Stable oxygen isotope Ice: - Thickness - Freeboard - Draft - Temperature - Salinity - Stable oxygen isotope - Crystallography and texture - Density Instruments: Snow: Folding scales, Spatula, Thermometer, Snow sampler, Magnifying glass, Salinometer, Temperature and thickness probes, scales Ice: Drills, corers, ice-thickness tape measures, thermometer, salinometer, band-saw, cross-polarising filter, scales The data are recorded in log books (scanned copies are included in this dataset) and have been transferred into the standard AAD sea-ice database templates (in excel format) for each station.

These data have been extracted from an Australian Antarctic Data Centre application, "Sea ice measurements database". The application has now been discontinued. The download file contains the extracted data, plus a sample data entry form. The extracted data are simply database tables that have been converted to csv format. Taken from the main page of the application: This archive contains in-situ measurements of Antarctic sea ice and snow cover properties, collected by many national programs over the past several decades. The data include physical, biological and biogeochemical measurements on ice cores and snow pit samples, as well as ice and snow thickness measurements from drilled transects across ice floes. The data are from all regions of the Antarctic pack ice in many different months of the year. Data can be submitted online using a standard proforma that can be downloaded from this site. The development of this site was a key recommendation from the International Workshop on Antarctic Sea Ice Thickness, held in Hobart, Australia in July 2006.

As part of Australian Antarctic Science project # 4298 and Antarctica New Zealand project K131A, a total number of 24 sea ice sites were sampled for bio-optical measurements along 2 transects on land-fast sea ice in McMurdo Sound (Antarctica) during November 2014. Measurements included hyperspectral surface irradiance measurements (TriOS ASS) as well as under-ice radiance measurements using a TriOS ARC (350 – 900 nm, 3.3 nm resolution) radiometer mounted to an L-arm. After completion of radiometric measurements, snow thickness was measured with a ruler and an ice core was collected directly above the radiometer location. Sea-ice freeboard (tape measure) and ice thickness (ice core length) were recorded. Ice core (9 cm internal diameter) bottom sections (lowermost 0.1 m of ice cores) were collected and were used for determination of algal pigment content (using HPLC) and spectral ice algal absorption coefficients (ap, ad, aph). Sea ice physical properties including vertical profiles of ice temperature and salinity profiles were collected at some specific locations along the transects, which were sampled near Little Razorback Island and near Cape Evans, McMurdo Sound.

In situ measurements of ice and snow thickness, and freeboard along an irregular transect on the fast, complementing the repeat ROV (Remotely Operated Vehicle) transects. During our deployment at Davis in 2015 logistics and environmental conditions permitted measurements along 4 transects. The location of the reference grid (ROV box) had its origin (x=0, y=0) at (-68.568904 degrees N,+77.945439 degrees E). Transects 1 – 4 started at x=60, x=70, x=80 and x=90 m and were sampled at y-positions of 0m, 0.5m, 1m, 2m, 4m, 8m, 16m, 32m, 64m, 128m, (256m, and 512m), respectively. Depending on working conditions the overall transect lengths varied from 128 – 512 m. Sampling dates for in situ ice physcis: Transect ID Date of sampling Zice and FB measured at Ice core taken at Snowpit measured at T1 19/11/2015 0, 0.5, 1, 2, 4, 8, … 64m. 0m, 128m, 512m 0m, 128m, 512m T2 23/11/2015 0, 0.5, 1, 2, 4, 8, … 64m. 0m, 128m, 512m 0m, 128m T3 29/11/2015 0, 0.5, 1, 2, 4, 8, … 64m. 0m, 128m 0m, 128m T4 02/12/2015 0, 0.5, 1, 2, 4, 8, … 64m. 0m, 128m 0m, 128m Ice cores and snow pits were collected at the 0m, 50m and 100m mark along the transect, where possible. Additionally, ice cores for density analysis were taken at a few of the ice-core sites for independent verification of ice density.