In this project a simplified computer model was developed to reflect the variation and influences of sea ice on the atmosphere. The model was incorporated into a global general circulation model. The data set resulting from the project consists of simulated sea ice characteristics (concentration etc.) available on a regular global grid. From the abstracts of some of the referenced papers: An observed ocean-drift data set is used as the basis of a wind-driven coupled ocean-sea-ice-atmosphere model including interaction and feedback. The observed characteristics of the Antarctic sea ice are described including the ice thickness, ice concentration and horizontal advection. The atmospheric model computes heat fluxes, sea-ice growth, changes in concentration and advection. Sensitivity studies show reasonable and stable simulations of the observed sea-ice characteristics for the present mean Antarctic winter climate. The response times and feedbacks of the ice-atmosphere system as represented by the model appear to allow scope for the development of some persistence of anomalies. To assess the sensitivity of the southern hemisphere circulation to changes in the fraction of open water in the sea ice we have conducted four experiments with a July 21-wave General Circulation Model (GCM) with this fraction set to 5, 50, 80 and 100%. The mean surface temperatures and the surface atmospheric temperatures over the sea ice increased as the water fraction increased and the largest changes were simulated adjacent to the coast. Significant anomalies in the surface heat fluxes, particularly those of sensible heat, accompanied the decrease in the sea ice concentration. Substantial atmospheric warming was simulated over and in the vicinity of areas in which leads were considered. In all but one experiment there were anomalous easterlies between about 40 and 60S with westerly anomalies further to the south. The surface pressure at high latitudes appears to change in a consistent fashion with the fraction of open water, with the largest changes occurring in the Weddell and near the Ross Seas. Some of the feedbacks which may enhance the responses here, but which are not included in our model are discussed. We present a simple parameterisation of the effect of open leads in a general circulation model of the atmosphere. We consider only the case where the sea ice distribution is prescribed (ie not alternative) and the fraction of open water in the ice is also prescribed and set at the same value at all points in the Southern Hemisphere and a different value in the Northern Hemisphere. We approximate the distribution of sea ice over a model 'grid box' as a part of the box being covered by solid ice of uniform thickness and the complement of the box consisting of open water at a fixed -1.8 degrees C. Because of the nonlinearity in the flux computations, separate calculations are performed over the solid sea ice and over the open leads. The net fluxes conveyed to the atmosphere over the grid box are determined by performing the appropriate area-weighted average over the two surface types. We report on an experiment designed to assess the sensitivity of the modelled climate to the imposition of a 50% concentration in the winter Antarctic sea ice. Significant warming of up to 6 degrees C takes place in the vicinity of and above the Antarctic sea ice and is associated with significant changes in the zonal wind structure. Pressure reductions are simulated over the sea ice, being particularly marked in the Weddell Sea region, and an anomalous east-west aligned ridge is simulated at about 60S. Very large changes in the sensible heat flux (in excess of 200 W per square metre) are simulated near the coast of Antarctica. Increasingly, many aspects of the study of Antarctica and the high southern latitudes are being aided by various types of numerical models. Among these are the General Circulation Models (GCMs), which are powerful tools that can be used to understand the maintenance of present atmospheric climate and determine its sensitivity to proposed changes. The changes in the ability of GCMSs used over the last two decades to simulate aspects of atmospheric climate at high southern latitudes are traced and it is concluded there has been a steady improvement in model products. The task of assessing model climates in high southern latitudes is made difficult by the uncertainties in the data used for the climatological statistics. It is suggested that the quality of the climates produced by most modern GCMs in many aspects cannot be said to be poor, especially considering the uncertainties in 'observed' climate. There is obviously need for improvements in both modelling and observations. Finally, some topics are highlighted in which the formulation of models could be improved, with special reference to better treatment of physical processes at high southern latitudes.

This dataset (provided as a series of CF-compatible netcdf file) consists of 432 consecutive maps of Antarctic landfast sea ice, derived from NASA MODIS imagery. There are 24 maps per year, spanning the 18 year period from March 2000 to Feb 2018. The data are provided in a polar stereographic projection with a latitude of true scale at 70 S (i.e., to maintain compatibility with the NSIDC polar stereographic projection).

Bridge-based observations of the pack ice within 1nm of supply- or research vessels are taken on all Antarctic AAS voyages while the vessel moves. Observations of sea-ice characteristics including ice concentration, ice- and snow thickness, floe-size distribution, surface features and ice type are recorded in IceBox, the underway sea-ice data acquisition tool. The ASPeCt sea-ice cards provide background and training material to support the sea-ice observers. The IceBox data sets are quality screened before they are integrated into the historical climate record for use in process studies, satellite calibration/validation, and operational or policy advise.

This dataset comprises high spatial- and temporal-resolution maps of coastal landfast sea ice (fast ice) distribution in the vicinity of the Cape Darnley Polynya in East Antarctica, in the June-November (winter-spring) periods of 2008 and 2009. The maps were derived from cross-correlation of pairs of spatially-overlapping Envisat Advanced Synthetic Aperture Radar (ASAR) images, using a modified version of the IMCORR algorithm to determine vectors of sea-ice motion (as described in Giles et al., 2011). Fast ice is then distinguished from moving pack ice by the fact that it is stationary. The raw ASAR WSM data (swath width 500 km) were processed using ENVI image processing software to produce geo-referenced images with a 75m pixel size. Use of SAR data ensures coverage uninterrupted by cloud cover or polar darkness. Image pairs were chosen with a time separation between 2 and 21 days. IMCORR processing of the image pairs for mapping fast ice follows Giles et al (2011) – using a reference tile size of 32x32 pixels and a search tile size of 64 x 64 pixels. A land mask was applied to avoid contamination from matches on stationary features over the continental ice sheet. The grid spacing was set to 16 x 16 pixels, so the images were over-sampled by a factor of 2 to provide a more dense set of results. Stationary fast ice vectors were chosen from the IMCORR results using a combination of the cluster search technique and a variation of the z-axis threshold technique as detailed in Giles et al (2011). The cluster search technique was applied to the IMCORR results from each image pair to derive the initial set of valid vectors – this set could contain both stationary fast ice vectors and non-stationary pack ice vectors. Due to registration errors in the image pairs, the stationary vectors will not necessarily be centred around zero, so using a simple window around the zero offset mark to differentiate the fast ice vectors was not possible. To select the stationary vectors, a 2D histogram was constructed from the X-Y vector displacements, and a 2D Gaussian was fitted to this histogram. The fast ice vectors will dominate because of the large image pair time separation and small search tile size, so the Gaussian peak should correspond to the centre of the stationary fast ice vectors. All vectors that are within 5 standard deviations of the Gaussian peak are tagged as valid fast ice vectors. This is a minor modification to the method of Giles et al (2011), who used a simple threshold cut on the z-axis of the 2D histogram to define the fast ice vectors. Data format – one fully annotated (self-describing) netCDF file per image pair containing latitude/longitude coordinates of the stationary fast ice vectors. This technique and dataset complement a lower resolution but longer-term dataset (2000-2014) derived from satellite MODIS visible and thermal infrared data. (AAS_4116_Fraser_fastice_mawson_capedarnley).

Observation on V3 commenced as the Aurora Australis departed Fremantle and concluded on the approach to Hobart. The SOCEP research objective is to detect and document cetacean sightings and relevant environmental and other information throughout the voyage. The BROKE-West multidisciplinary voyage provides an opportunity to correlate sightings data with oceanographic and biology research conducted by other programs. Search effort is conducted over a broad range of weather conditions. The majority of Antarctic species are medium to large whales, with cues that can be detected in relatively high Beaufort sea states up to and including Beaufort Sea State 7. Observers search for whales while ever light, weather and sea conditions are suitable unless the vessel is stopped (e.g. CTD stations) or traveling slowly (e.g. trawling). Data are recorded using a laptop computer-based sighting program (Wincruz for Logger v3) that automatically logs under-way data from the ship's system including GPS position, ship course and speed, wind direction and speed, and also downloads time and date when required (F1 key). Data Collection In the preferred and highest level of (Full Effort) two observers are positioned on the port (Port) and starboard (Starboard) sides of the flying bridge (wheelhouse roof). The search area is an arc 180 degrees ahead to abeam of the vessel, primarily with the naked eye and augmented by the use of Fujinon 7x50 binoculars. A third observer (Tracker) is also stationed on the flying bridge. This person's role is to positively identify species, numbers and behaviour, particularly in the case of distant sightings, with the aid of Fujinon 25 x 150 binoculars (BigEyes). This team member also captures digital video footage of cetacean sightings when appropriate. The fourth rostered team member, the Central Logger (CL) is located on the bridge and communicates with those on the flying bridge via hand-held radio transceiver. The role of the CL is to record all relevant data on the Logger laptop computer. When in sea ice, a fifth member of the team ('Duplicate Identifier') is rostered to collect sea ice digital still images and video, and enter ice data in the SeaIce page in Logger. The CL monitors the effort activity and progressively updates as necessary general information such as search effort, observers, weather, sea conditions. Search effort is dropped a lower level of effort (CAS Effort), if visibility is determined to be too poor for Full Effort due to some combination of adverse weather conditions that precluded detection of most species (i.e. strong winds, fog, and large swell, confused swell, high sea state). If conditions become too poor to survey, or if the ship is traveling slowly or stopped, the effort is terminated (Off Effort). At such times the CL is generally rostered to remain on the bridge to ensure that passing whales do not go unreported, and to alert the rest of the team when the ship begins transiting at speed again or if visibility improves. Sightings When observers report whale sightings the CL enters the time, angle and distance from vessel, species identification, number of animals, sighting cue, behaviour and presence of ice and ancillary data. Cetaceans are identified to the lowest taxonomic level possible. Positive species identification is made only when there is certainty. Best, high and low estimates of group size are recorded for each sighting, and where more than one observer made an estimate, the final record is arrived at by consensus. Photographic records of cetaceans (and other wildlife and habitat) are collected opportunistically using digital cameras. Other Wildlife Seal and penguin species are logged while in sea ice, and opportunistically elsewhere. Flying birds within 100 metres of the ship are logged half-hourly, and large flocks are logged when observed. Other Event Occurrences such as the sighting or marine debris are logged as they are observed. Sea Ice Data Sea ice observations are recorded in Logger every 10 minutes while in transit in sea ice unless the ship is stopped or transiting slowly. Sea ice data are based on observations within a 1km 90 degree radius of the ship on the port side. A buoy of known diameter is suspended just above the waterline in front of the bridge to assist with estimates of ice and snow thickness. Sea ice still digital images are taken every 10 minutes while in transit in sea ice (unless transiting slowly), coinciding with SeaIce data recording in Logger. Sea Ice continuous video is taken for ten minutes each half-hour, showing the bow and horizon. The images and video assist in post cruise validation of sea ice thickness and assessment of the 1km radius for sea ice data collection. Sea ice habitat images are also captured when/where minke whales are sighted. Acronyms % Species 1 Percentage of group made up by Species 1 % Species 2 Percentage of group made up by Species 2 % Species 3 Percentage of group made up by Species 3 Bearing Bearing of sighting, in degrees, relative to the ship Beaufort Sea state assessment using Beaufort Scale (1-12) Berg Count No of icebergs 180 degrees ahead Best school size Best estimate of the number in group Casual observations (CAS) Lower level of Effort e.g. fewer observers Duplicate Identifier Person gathering/entering ice observations/images Dynamics Changes to the pod's composition. Effort Status Classification of level of observation effort End Time Time sighting observation ended Est distance Estimated distance from ship in nm. Floe Size Descriptive of size/nature of ice flows Full effort Highest level of observation effort Glare strength Classification of glare as it effects visibility Habitat Bathymetry Determined by reference to ship's chart High school size Highest estimate of the number in group Ice Conc Concentration of ice, in tenths Ice Thick Ice thickness in cm Ice Type Descriptive nature of ice Image File Identification number allocated to image taken at time of data entry In or Near Ice Ice conditions where wildlife was sighted Initial cue What first drew the observer's attention to the sighting. Left Glare Left extremity of glare Low school size Lowest estimate of the number in group Method Whether sighting was made using naked eye, 7x50 binoculars or 25x150 (Big-eye) binoculars Minke Vis Estimate of the distance at which a minke whale blow could be seen in prevailing conditions Notes For Recorder's additional information and comments Observer Person reporting the sighting Open Water Overall ice/water situation Port Observer monitoring the ocean on the port side Primary Ice Obs. Observations of thickest ice type Reaction The animal's reaction to the ship Recorder Person entering data into Logger Right Glare Right extremity of glare Secondary Ice Obs. Observations of second-thickest ice type Sightability Assessment of overall viewing conditions Sighting No Progressive numbering of whale sightings by Logger (default) Snow Thick Snow thickness in cm Snow Type Descriptive of snow on ice Species 1 When multiple species are being reported, with the species in greatest number listed first Starboard Observer monitoring the ocean on the starboard side Swell Code Descriptive of ocean swell Swell Direction Compass direction from which swell moving. Swim direction Animal's swim direction in degrees relative to the ship's heading Tertiary Ice Obs Observations of third-thickest ice type Topog Descriptive of ice topography e.g. ridging Total Ice Conc Ice concentration in tenths Tracker Observer using BigEyes binoculars to identify species, and assisting other observers generally Weather Code Weather conditions effecting visibility An excel spreadsheet containing a full list of terms used in the observation logs is available for download from the URL given below. This work was completed as part of ASAC projects 2253, 2655 and 2679 (ASAC_2253, ASAC_2655, ASAC_2679).

The distribution and abundance of ice-associated copepods in the fast ice of the Australian Antarctic Territory were investigated over a distance of approximately 650 km between October and December 1995. The six sites where collections were made were: offshore from Mawson station, Larsemann Hills (including Nella Bay), Rauer Islands (ice edge near Filla Is), O'Gorman Rocks and Bluff Island near Davis Station, and Murphy Rocks in the northern Vestfold Hills. Ice cores were obtained using SIPRE ice augers. Five to ten cores were collected along transects several km in length. Thickness of sea ice and snow cover were measured at each sampling site. Chlorophyll a concentrations were determined for each core. Copepods were isolated from the melted core water and identified and counted. Zooplankton tows were also made at each site where cores were collected. Nine species of copepods were identified from the cores. However, of these, only three were recorded regularly: Paralabidocera antarctica, Drescheriella glacialis and Stephos longipes. The abundance of copepods ranged between 0 and 147/L. The highest densities were recorded at the Larsemann Hills and the lowest at Murphy Rocks. Within the cores, the highest abundances were found in the bottom 10 cm of ice, irrespective of the species. Chlorophyll a concentrations ranged between 0.9 and 373 mg/m3. Data available: excel files containing sampling dates, sampling sites and abundances (number per L) of three dominant sea ice copepods, Paralabidocera antarctica, Drescheriella glacialis, Stephos longipes. Data are presented for developmental stages (nauplii, copepodites and adults) where available. Totals are also provided. Vertical distribution in some cores is also provided. Chlorophyll a concentrations (ug/L) provided for most sites. Detailed information about each of the spreadsheets is provided below: The chlorophyll spreadsheet shows chlorophyll concentrations for 5 sites in the AAT. The column headings are: core - reference number of the core collected subsection - depth in the core in cm volume - vol of melted core water volume added - 1 L of filtered seawater for melting % original - amount of total that core water represents (i.e. minus the 1L added) aliquot - volume subsampled for chlorophyll analysis acetone - amount added (mL) for extraction 750, 664, 647, 630 - wavelengths where absorbance was measured chloro a - amount of chlorophyll a in the sample ug/L - chloro a expressed as a concentration The spatial spreadsheet shows species abundances of three copepods at 4 sites N1 to NVI - nauplius stage 1 to 6 of a species CI to CVI - copepodite stage 1 to 6 of a species F or M - female or male of copepodite stage 5 or 6 1,1 etc - cores 1 and 2 from site 1 within a major location (e.g. 2 cores close together in the Larsemann Hills) The temporal spreadsheet shows abundances over time at 2 sites (O'Gorman Rocks, Bluff Is) near Davis and two species (Paralabidocera antarctica and Drescheriella glacialis) on several sampling dates N1 to N3 - total nauplii in each of three cores (i.e. not separated into stages as above) C1 to C3 - total copepodites A1 to A3 - total adults Then at the bottom are the means of each three cores.

Imagery of Aurora Australis and sea ice captured by a 'quadcopter' (Inspire) drone launched from the ship

During the winter and spring of 2002, underwater calling rates were measured near mid-day on an opportunistic basis at 7 breeding sites and, at two breeding sites, over 24 hour periods once a month. The data were analysed with respect to reproductive season (early ice formation, prebreeding, pupping and mating) and if the recordings were made when it was dark or twilight/light. Taken from the abstract of the paper referenced below: Underwater vocalisation monitoring and surveys, both on ice and underwater, were used to determine if Weddell seals (Leptonychotes weddellii) near Mawson Station, Antarctica, remain under the fast ice during winter within close range of breeding sites. Daytime and nighttime underwater calling rates were examined at seven breeding sites during austral winter and spring to identify seasonal and diel patterns. Seals rarely hauled out at any of the sites during winter, although all cohorts (adult males, females, and juveniles) were observed underwater and surfacing at breathing holes throughout winter (June-September) and spring (October-December). Seal vocalisations were recorded during each sampling session throughout the study (n=102 daytime at seven sites collectively, and n=5 24-h samples at each of two sites). Mean daytime calling rate was low in mid-winter (July) (mean = 18.9 plus or minus 7.1 calls per minute) but increased monthly, reaching a peak during the breeding season (November) (mean = 62.6 plus or minus 15.7 calls per minute). Mean nighttime calling rate was high throughout the winter and early spring (July-October) with mean nocturnal calling rate in July (mean = 61.8 plus or minus 35.1 calls per minute) nearly equal to mean daytime calling rate in November (during 24-h daylight). Reduced vocal behaviour during winter daylight periods may result from animals utilising the limited daylight hours for nonvocal activities, possibly feeding. The following study sites were among those used in this project (provided by Phil Rouget): - Forbes site (identified as Site 6 in the paper) is located at Forbes Glacier (approx. 0.5 km to the west of the glacier tongue and approximately 200 meters offshore of the mainland). (67 degrees 35.256 minutes S, 62 degrees 16.756 minutes E) - Kista site is located in the middle of Kista Strait (site 7 in the Marine Mammal Science paper). (67 degrees, minutes 33.840 S, 62 degrees 47.402, minutes E) - SPA site was our site located just west of the western boundary of the SPA which itself is located west of Mawson and east of Forbes Glacier. (Site 2 in Marine Mammal Science paper). (67 degrees 35.179 S, 62 degrees 25.425 minutes E) - McDonald Islands (or Rocks) was the site located North/NorthWest of Kista Strait, as it is named so on the Framens Mtn. Nautical Chart. From memory, it was approximately 12 km north/north west of Mawson Station. (This was site 5 in the Marine Mammal Science paper). (67 degrees 29.414 minutes S, 62 degrees 41.011 minutes E) - Stewart Rocks (also named Sewart Rocks on an alternative map) is located due north of Mawson Station, also by about 12 km. (East of McDonald site, and North East of Kista). This was site 4 in the Marine Mammal Science paper. (67 degrees 29.933 minutes S, 62 degrees 51.765 minutes E) - Anderson Rocks is an extensive group of rocky islets west of Auster Island (approximately 6-7 km offshore). This was site 3 in the Marine Mammal Science paper. (67 degrees 26.445 minutes S, 63 degrees 25.414 minutes E) - SEAL MO was located just north of Macey Hut by about 2 km. This was site 1 in the Marine Mammal Science paper. (67 degrees 23.399 minutes S, 63 degrees 47.977 minutes E) - Aside from SEAL MO and SPA, the names from all these sites are indicated in the Framnes Mountain Chart. An image showing the locations of the fields sites is also part of the download file. The fields in this dataset are: Site Period Day Calling rate photoperiod Sun time

This dataset contains observations of ice conditions taken from the bridge of the RV Aurora Australis during SIPEX 2012, following the Scientific Committee on Antarctic Research/CliC Antarctic Sea Ice Processes and Climate [ASPeCt] protocols. See aspect.antarctica.gov.au Observations include total and partial concentration, ice type, thickness, floe size, topography, and snow cover in each of three primary ice categories; open water characteristics, and weather summary. The dataset is comprised of the scanned pages of a single logbook, which holds hourly observations taken by observers while the ship was moving through sea-ice zone. The following persons assisted in the collection of these data: Dr R. Massom, AAD, Member of observation team Mr A. Steer, AAD, Member of observation team Prof S. Warren, UW(Seattle), USA, Member of observation team Dr J. Hutchings, IARC, UAF, USA, Member of observation team Dr T. Toyota, Inst Low Temp Science, Japan, Member of observation team Dr T. Tamura, NIPR, Japan, Member of EM observation team Dr G. Dieckmann, AWI, Germany, Member of observation team Dr E. Maksym, WHOI, USA, Member of observation team Mr R. Stevens, IMAS, Trainee on observation team Dr J. Melbourne-Thomas, ACE CRC, Trainee on observation team Dr A. Giles, ACE CRC, Trainee on observation team Ms M. Zhia, IMAS, Trainee on observation team Ms J. Jansens, IMAS, Trainee on observation team Mr R. Humphries, Univ Wollengong, Trainee on observation team Mr C. Sampson, Univ Utah, USA, Trainee on observation team Mr Olivier Lecomte, Univ Catholique, Louvain-la-Neuve, Belgium, Trainee on observation team Mr D. Lubbers, Univ Utah, USA, Trainee on observation team Ms M. Zatko, UW(Seattle), USA, Trainee on observation team Ms C. Gionfriddo, Uni Melbourne, Trainee on observation team Mr K. Nakata, EES, Japan, Trainee on observation team

These data describe pack ice characteristics in the Antarctic sea ice zone. These data are in the ASPeCt format. National program: United States Vessel: Nathaniel B. Palmer Dates in ice: 1 Sept 2007 - 31 Oct 2007 Observers: Penelope Wagner, John Pena, Sarah Anderson and others. Summary of voyage track: 06/09 3 GMT first record of ice edge at approx. 63 degrees 22 S, and 68 degrees 25 W toward Palmer Station, Antarctica in the Amundsen Sea due to electrical fire that began in Drake's Passage en route to the Bellingshausen Sea, Antarctica. 19 GMT arrived at NBP at Palmer Station, Antarctica at 64 degrees 46S and 64 degrees 04W to respond to safety protocol with NSF and Raytheon. 08/09 18:30 GMT depart Palmer Station toward Punta Arenas, Chile port. 09/09 22 GMT reach ice edge toward Chile. 24/09 17 GMT first record of ice edge at approx. 66 degrees 47S and 89 degrees 05W toward ice station Belgica in Bellingshausen Sea, Antarctica. 27/09 23GMT NBP parked at approximately 70 degrees 41S and 90 degrees 58W at Ice Station Belgica to perform 4 week station work. 24/10 10:30 GMT depart Ice Station Belgica toward Punta Arenas, Chile 27/10 8GMT reached ice edge. Total observations: 192 The fields in this dataset are: SEA ICE CONCENTRATION SEA ICE FLOE SIZE SEA ICE SNOW COVER SEA ICE THICKNESS SEA ICE TOPOGRAPHY SEA ICE TYPE RECORD DATE TIME LATITUDE LONGITUDE OPEN WATER TRACK SNOW THICKNESS SNOW TYPE SEA TEMPERATURE AIR TEMPERATURE WIND VELOCITY WIND DIRECTION FILM COUNTER FRAME COUNTER FOR FILM VIDEO RECORDER COUNTER HH:MM:SS VISIBILITY CODE CLOUD IN OKTAS WEATHER CODE COMMENTS