Direct Numerical Simulation (DNS) was used to study the effect of sloping the ice-shelves on the dissolution/melt rate at the ice-ocean interface. The simulations were done on the HPC Raijin at NCI, Canberra over March 2015 to June 2017. Numerical experiments were carried out over a range of slope angle (5 degrees – 90 degrees) of the ice-shelves measured from the horizon. Turbulent flow field is simulated over the domain length of 1.8 m, (for slope angle greater than or equal to 50 degrees) and 20 m (for slope angle less than or equal to 20 degrees) respectively; the flow-field is laminar otherwise. A constant ambient temperature 2.3 degrees C and salinity 35 psu is maintained throughout the simulations. The DNS successfully resolved all possible turbulence length scales and relative contributions of diffusive and turbulent heat transfer into the ice wall is measured. Data available: Excel file Meltrate_vs_slopeangle_lam_turb.xlsx contains both simulated laminar and turbulent dissolution/melt rate as a function of slope angle along with their analytical values based on laminar and turbulent scaling theory respectively.

Direct Numerical Simulation (DNS) was used to study the effect of sloping the ice-shelves on the dissolution/melt rate at the ice-ocean interface. The simulations were done on the HPC Raijin at NCI, Canberra over March 2015 to June 2017. Numerical experiments were carried out over a range of slope angle (5 degrees – 90 degrees) of the ice-shelves measured from the horizon. Turbulent flow field is simulated over the domain length of 1.8 m, (for slope angle greater than or equal to 50 degrees) and 20 m (for slope angle less than or equal to 20 degrees) respectively; the flow-field is laminar otherwise. A constant ambient temperature 2.3 degrees C and salinity 35 psu is maintained throughout the simulations. The DNS successfully resolved all possible turbulence length scales and relative contributions of diffusive and turbulent heat transfer into the ice wall is measured. Data available: Excel file Profile_salinity_temperature_velocity.xlsx contains along-slope velocity, temperature and salinity as a function of wall normal distance for slope angle 50 degrees, 65 degrees and 90 degrees respectively for the domain length 1.8 m.

This dataset contains data resulting from the measurement of brine samples extracted from the sea-ice during the 2012 SIPEX 2 (Sea Ice Physics and Ecosystems Experiment) marine science voyage. The Brine was collected from partially drilled holes in the ice using suction. In some of these cases the brine analysed came from holes which correspond to permeability measurements. In these cases a core number is associated with the brine data which will correspond to the core number in the permeability data set. Brine was also made on the ship by repeatedly freezing sea water collected from site 8. Measurements of the electrical permittivity of the brine were measured from 200MHz-4GHz with varying temperature and salinity. The measurements were carried out using the FieldFox portable network analyser from Agilent technologies along with the Agilent 85070e high temperature dielectric probe. Typically the brine was cooled and measured as the temperature changed over time once removed from a freezer. Some samples were measured before and after filtering out any biology that may have been present to see any biological effect on the electrical properties of the brine, in particular any effect extra cellular carbon may have. Measurements of the biology in the brine were performed by Sarah Ugalde please refer to the biophysical folder for further information and the data. The actual permittivity measurements can be found in the Brine_Frequency_Temp Excel file. In the file each set of measurements has its own tab. Each measurement has a temperature and salinity associated with it. For a variability study measurements were repeated on some samples in which case the tab contains the sample name as well as an index indicating which repetition the data corresponds to. For example Core 85 6 would be the 6th measurement for core 85. You will also find the Excel file Brine_Calibration_Record which logs each calibration preformed before each measurement. The calibration for a given brine measurement has the same name as that brine measurement so that they can be matched. The permittivity measurements for each frequency, salinity and temperature are given in the real (e') and imaginary part (e").

The dataset lists key biogeochemical parameters measured in sea ice during the SIPEX2 voyage, including dissolved and particulate iron and other trace metals, macronutrients (silicic acid, nitrates+nitrite, phosphoric acid and ammonium), iron binding organic ligands, dissolved and particulate organic carbon, Cholophylla, thermodynamics (temperature, salinity, brine volume and Rayleigh number). All sampling bottles and equipment were decontaminated using trace metal clean techniques. Care was taken at each site to select level ice with homogeneous snow thickness. At all the stations, the same sampling procedure has been used : Firstly, snow was collected using acid cleaned low density polyethylene (LDPE) shovels and transferred into acid-cleaned 3.8 l LDPE containers (Nalgene). Snow collected was analysed for temperature, salinity, nutrients, unfiltered and filtered metals. Snow thickness was recorded with a ruler. Ice cores were collected using a non-contaminating, electropolished, stainless steel sea ice corer (140 mm internal diameter, Lichtert Industry, Belgium) driven by an electric power drill. Ice cores were collected about 10 cm away from each other to minimise between-core heterogeneity. A first core was dedicated to the temperature, salinity and Chlorophyll a (Chla). To record temperature, a temperature probe (Testo, plus or minus 0.1 degrees C accuracy) was inserted in holes freshly drilled along the core every 5 to 10 cm, depending on its length. Bulk salinity was measured for melted ice sections and for brines using a YSI incorporated Model 30 conductivity meter. Chla is processed on board using a 10 AU fluorometer (turner Designs, sunnyvale California). The total length of this core is cut in sections of 7 cm. The second core is dedicated to the POC/PON (Particulate Organic Carbon/ Particulate Organic Nitrogen), DOC (Dissolved Organic Carbon) and nutrients. Six sections of 7 cm were sub-sampled from this core. The six sections were chosen so that two top, two intermediate and two basal sections. Two cores are taken for the trace metal analysis. Those cores were directly triple bagged in plastic bags (the inner one is milli-Q washed) and frozen at -20degrees C until analysis at the laboratory. Brine samples were collected by drainage from “sack holes”. Brines and under ice seawater (~1 m deep) were collected in 1 l Nalgene LDPE bottles using an insulated peristaltic pump and acid cleaned C-flex tubing (Cole Palmer). All samples were then transported to the ship as quickly as possible to prevent further freezing. Samples were used to analyse unfiltered and filtered metals, Chla, POC/PON, nutrients and DOC. Filtration for filtered metals was completed on board using a peristaltic pump and a 0.2 microns cartridge filter. All the unfiltered and filtered metals collected were acidified (2 ppt HCl seastar) and stored at room temperature until analysis at the laboratory. Nutrients, DOC and filters for POC/PON were stored frozen at -20 degrees C until analysis at Analytical Service Tasmania, Hbart. Chla filtrations and analysis were completed on board. The file "SIPEX2 sea ice data" lists key biogeochemical parameters in sea ice cores, snow, brine and underice seawater (1m depth) collected during the SIPEX2 voyage (64.26-65.15S/116.44-120.58E) carried out between the 26th of september and 29th of october 2012. The acid-cleaning protocols for sample bottles and equipment followed the guidelines of GEOTRACES (www.geotraces.org). Contamination-free ice coring equipment developed by Lannuzel et al. (2006) was used to collect ice cores. Ice cores were triple bagged and stored at -18 degrees C until further processing in the home laboratory. Ice cores were then sectioned under a class-100 laminar flow hood (AirClean 600 PCR workstation, AirClean System) using a medical grade stainless steel bonesaw (Richards Medical), thouroughly rinsed with ultra-high purity water (18.2 MO), and ice sections were then allowed to melt at ambient temperature in acid-cleaned 3 L Polyethylene (PE) containers. Melted sea-ice sections were then homogenized by a gentle shake and filtered through 0.2 microns pore size polycarbonate filters (Sterlitech, 47 mm diameter) using Teflon(R) perfluoroalkoxy (PFA) filtration devices (Savillex, USA) connected to a vacuum pump set on less than 2 bar to obtain the particulate (greater than 0.2 microns) and dissolved (less than 0.2 microns) metal fractions. The collected filtrates (less than 0.2 microns) were acidified to pH 1.8 using Seastar Baseline(R) HCl (Choice Analytical) and stored at ambient temperature until analysis in the home laboratory. The filters retaining the particulate material were stored frozen in acid-clean petri dishes until further processing. Standard physico-chemical and biological parameters such as sea-ice and snow thicknesses, in situ ice temperature, sea-ice and brine salinities, ice texture, chlorophyll a (Chla), macro-nutrients (nitrate+nitrite (NOx), phosphate (PO43-), silicic acid (Si(OH)4-) and ammonium (NH4+)), dissolved organic carbon (DOC), and particulate organic carbon and nitrogen (POC and PON) were also determined in each sample at Analytical Service Tasmania (Hobart, Australia) within 6 months of sample collection. Dissolved inorganic nutrients were determined using standard colorimetric methodology (Grasshoff et al., 1983) as adapted for flow injection analysis using an auto-analyzer. Theoretical brine volume fractions (Vb/V) were calculated using in situ ice temperatures and bulk ice salinities and relationships from Cox and Weeks (1983). The full ice core length was examined under crossed-polarised light to identify the texture (i.e., columnar vs granular) according to the method of Langway (1958). Preparation of the thin sections took place in a container kept at -25 degrees C. The thin sections were obtained by cutting vertical sections of about 6 mm thick using a band saw. Ice sections were then thinned down using a microtome blade to reach a final thickness of 3 - 4 mm and observed under cross-polarized lights The acidified filtrates were diluted 5 times, using 2 % v:v ultrapure HNO3 (Seastar Baseline, Choice Analytical) and dissolved metals concentrations were determined directly using sector field inductively coupled plasma magnetic sector mass spectrometry (SF-ICP-MS; Element 2) following the method described in Lannuzel et al. (2014). Filters retaining particulate material (greater than 0.2 microns) were digested in a mixture of strong, ultrapure acids (750 micro litres 12N HCl, 250 microlitres 40% HF, 250 microlitres 14N HNO3) in 15 mL Teflon(R) perfluoroalkoxy (PFA) (Savillex, USA) on a Teflon coated graphite digestion hot plate housed in a bench-top fume hood (all DigiPREP from SCP Science, France) coupled with HEPA(R) filters to ensure clean air input at 95 degrees C for 12 h, then dry evaporated for 4 h and re-suspended in 2 % v:v HNO3 (Seastar Baseline, Choice Analytical). The procedure was applied to filter blanks and certified reference materials BCR-414 and MESS-3 to verify the recovery of the acid digestion treatment. The concentrations of particulate metals were then determined by SF-ICP-MS (Bowie et al., 2010). Results for procedural blanks, limits of detection and certified reference materials were found fit for purpose. The file "SIPEX2 TMR data" lists macro-nutrients concentrations, as well as dissolved iron concentrations collected using a Trace Metal Rosette (TMR) deployed over 1000m depth in the sea ice zone. Dissolved iron (DFe) and iron in the 2+ redox state (FeII) in nanomoles per Litre (nmol/L) were measured onboard using FIA-CL technique explained in Schallenberg et al (2015). Standard deviation associated with the analysis of the samples is indicated by "SD". Dissolved Fe(III): Dissolved Fe in this study is operationally defined as the Fe fraction that passes through a 0.2 microns filter. A modified flow injection analysis (FIA) method was used to measure dFe that relies on the detection of Fe(III) with the chemiluminescent reagent luminol (de Jong et al., 1998; Obata et al., 1993). Samples and standards were treated with hydrogen peroxide (H2O2; final concentration = 10 micro mols) at least 1 hour prior to measurement to oxidize any Fe(II) that might be present (Lohan et al., 2005). The system buffers the samples in-line to pH = 4 before passing them for 3 minutes through a pre-concentration column packed with 8-hydroxyquinoline chelating resin (8-HQ). A solution of 0.3 M HCl (Seastar) then elutes Fe(III) from the resin and mixes with 0.8 M ammonium hydroxide (NH4OH), 0.1 M H2O2 and 0.3 mM luminol containing 0.3 mM triethylenetetramine (TETA) and 0.02 M sodium carbonate (Na2CO3), yielding an optimum luminol chemiluminescence reaction pH of 9.5. The resulting solution is passed through a ~5 m mixing coil maintained at 35 degrees C before being pumped to the flow cell mounted in front of a photo-detector. System blanks were 0.014 plus or minus 0.004 nM, yielding a detection limit (3 x blank standard deviation) of 0.013 nM. Results for SAFe reference materials for Fe were in good agreement with consensus values (see Table 1). Dissolved Fe(II): Fe(II) was determined by luminol chemiluminescence detection following the approach of Hansard and Landing (2009) but without sample acidification. Sampling began within minutes after the first Niskin bottle (always from the surface) arrived in the clean container. Samples were analyzed within 2 minutes of filtration and were pumped simultaneously with the luminol reagent into a spiral flow cell made of flexible Tygon(TM) tubing (ID = 0.7 mm) that was mounted in front of a photomultiplier tube (Hamamatsu H9319-01) in a custom-made light-tight box. Flow rates for luminol and sample were ~4.5 mL/min. The photomultiplier tube was operated at 900 V with a 200 ms integration time. Photon counts were recorded using FloZF software (GlobalFIA) and were averaged over 10 second intervals with 5 replications for each sample and standard. The relative standard deviation of these repeat measurements was between 1 and 3%. The luminol recipe for 1 L reagent is as follows: 0.13 g luminol, 0.34 g Na2CO3, 40 mL concentrated NH4OH and 10-12 mL concentrated HCl (Seastar). This results in 0.75 mM luminol with 3.2 mM Na2CO3. The pH of the reagent is adjusted to ~10.0 with small amounts of NH4OH and HCl. It was found that luminol sensitivity increases with age, so batches were prepared well in advance and used up to 3 months later. Fe(II) calibration curves were obtained with Fe(II) standard additions in the range 0-100 pM. A 10 mM standard of ammonium iron(II) sulfate hexahydrate was prepared fresh in 0.1 M Seastar HCl and considered stable in the fridge for up to a month. From this stock solution, intermediate standards (50 micro mols and 50 nM) were prepared in 0.05 M Seastar HCl no more than 10 minutes prior to measurement. Standards were added to seawater that had been collected at earlier stations in the cruise and been left in the dark for greater than 24 hours. Previous investigators (e.g., Rose and Waite, 2001) have commented on the light-sensitivity of the luminol reagent, and it is therefore frequently stored in the dark.

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.

This work was completed as part of the SIPEX - Sea Ice Physics and Ecosystem eXperiment - voyage. Adapted from the SIPEX website: During SIPEX we investigated the biogeochemistry of iron (Fe), including a comprehensive examination of its distribution, speciation (i.e. the different forms of Fe), cycling and its role in fuelling sea ice-based and pelagic algal communities. A major part of this research concentrated on the influence of organic exopolysaccharides (EPS) on Fe solubility and its bio-availability. The distribution of other bioactive trace elements was also examined as a means of fingerprinting the source(s) of Fe, as well as indicating their biological requirements. ######### Data on the small- to medium scale (0.1-1000 m) spatial and temporal distribution of Fe and EPS in sea ice cores, surface snow, brine and underlying seawater were determined in each sampled medium by the interdisciplinary team working on the SIPEX project (AAS 3026) in the East Antarctic sector in September/October 2007. Data include Chlorophyll a, salinity, temperature, sea-ice thickness, ice texture analysis, macro-nutrients (nitrate, phosphate, silicate), oxygen stable isotopes, POC and DOC, EPS, iron. This work was completed as part of AAS (ASAC) project 3026. See the parent metadata record (ASAC_3026) for more information.

Metadata record for data from AAS (ASAC) project 3026. Public This project will assess the importance of the trace micro-nutrient element iron to Antarctic sea-ice algal communities during the International Polar Year (2007-2009). We will investigate the biogeochemistry of iron, including a comprehensive examination of its distribution, speciation, cycling and role in fuelling ice-edge phytoplankton blooms. A significant part of this research will concentrate on the the influence of organic exopolysaccharides on iron solubility, complexation and bioavailability, both within the ice and in surrounding snow and surface seawater. This innovative research will improve our understanding of key processes that control the productivity of the climatically-important Antarctic sea-ice zone. Project objectives: This project will assess the importance of the trace element iron (Fe) as a micro-nutrient to seasonal sea-ice algal communities in the Australian sector of Antarctica during the International Polar Year (2007-09). We will investigate the biogeochemistry of Fe, including a comprehensive examination of its distribution, speciation, cycling and role in fuelling ice-edge phytoplankton blooms. A significant part of this research will concentrate on the influence of organic exopolysaccharides (EPS) on Fe solubility and complexation (and hence bioavailability), both within the ice and in surrounding surface waters. This innovative research will improve our understanding of key processes that control the productivity of the climatically-important Antarctic sea-ice zone. Specifically, in this project: - The biogeochemical behaviour of Fe in sea-ice with regards to EPS complexation, and key physicochemical and biological data will be evaluated. - The bioavailability of Fe for phytoplankton growth during sea-ice melt will be investigated through laboratory-based experiments designed to mimic spring conditions. - The distribution of other bioactive trace elements in the Antarctic sea-ice environment will be examined as a means of fingerprinting the source(s) of Fe, as well as indicating their biological requirement. Taken from the 2008-2009 Progress Report: Progress against objectives: In the last twelve months we achieved all the objectives planned for the shore-based sample processing and analysis from the SIPEX voyage (fieldwork September-October 2007). An extensive and unique seasonal and spatial data set was put together including parameters such as ice texture, salinity, temperature, Chlorophyll a, particulate organic carbon (POC), dissolved organic carbon (DOC), macro-nutrients (silicate, phosphate and nitrate), and exoplysaccharides (EPS, using both alcian blue and PSA methods). Dissolved iron (dFe) and total dissolvable iron (TDFe) were analysed by flow injection - chemiluminescence (FIA-CL) analysis in Hobart. Polycarbonate (PC) filters (Nuclepore 0.2 micron pore size) retaining particulate metals were digested in a mixture of strong, ultrapure acids (750 micro litre 12N HCl, 250 micro litre 40% HF, 250 micro litre 14N HNO3) on a hotplate at 125 degrees C for 8 h. The procedure was successfully applied to plankton, estuarine and river sediment reference materials to verify the recovery of the digestion treatment. The concentrations of particulate iron (PFe) were determined by high resolution ICP-MS at the Central Science Laboratory at UTAS. This data has been quality-controlled, analysed, interpreted and published (see below). Due to the fact that logistical support was not possible for 2008/09 (insufficient berths at Casey Station) despite approval of our project, the field component of the project was delayed. Taken from the 2009-2010 Progress Report: Progress against objectives: Monthly Milestones of PhD student Pier van der Merwe: Successful Antarctic research expedition occurred in Oct-Dec 2009 at Casey Station Antarctica with logistical support from AAS project #3026 (flight on FA02 and berths at Casey station as well as field support of personnel). OCT-DEC 2009 - Antarctic time series data collection and processing successful. Data analysis scheduled for Jan - Mar. Write up of last paper(s) scheduled for Mar-June. Final completion of thesis due in August. DEC - Chlorophyll a data analysed JAN - FIA and CLECSV analyses start simultaneously FEB - Finish FIA analyses and attend Ocean science meeting in Portland Oregon. MAR - Finish CLECSV analyses and run POC and PFe digestions and analyses. Scheduled with Thomas Rodemann and Ashley Townsend at the CSL, UTAS. APR - MAY Data analysis and write up of 3rd paper, and possibly 4th based on field work at Casey station Oct-Dec 2009. See the child metadata records for more information about the data.

More than 50 scientists from eight countries conducted the Sea Ice Physics and Ecosystem eXperiment 2012 (SIPEX-2). The 2012 voyage built on information and observations collected in 2007, by re-visiting the study area at about 100-120 degrees East. This was the culmination of years of preparation for the Australian Antarctic Division and, more specifically, the ACE CRC sea-ice group who lead this international, multi-disciplinary, sea ice voyage to East Antarctica. Work began at the sea-ice edge and penetrated the pack ice towards the coastal land-fast ice. The purpose of SIPEX-2 was to investigate relationships between the physical sea-ice environment, marine biogeochemistry and the structure of Southern Ocean ecosystems. While the scientists and crew did not set foot on Antarctic terra firma, a number of multi-day research stations were set up on suitable sea ice floes, and a range of novel and state-of-the-art instruments were used. These included: A Remotely Operated Vehicle (ROV) to observe and film (with an on-board video camera) krill, and to quantify the distribution and amount of sea ice algae associated with ice floes. An Autonomous Underwater Vehicle (AUV) to study the three-dimensional under-ice topography of ice floes. Helicopter-borne instruments to measure snow and ice thickness, floe size and sea ice type. Instruments included a scanning laser altimeter, infrared radiometer, microwave radiometer, camera and GPS. Sea ice accelerometer buoys to measure sea ice wave interaction and its effect on floe-size distribution. Customised pumping systems and light-traps to catch krill from below the ice and on the sea floor. Available at the provided URL in this record, is a link to a file containing the locations of all ice stations from this voyage.