EARTH SCIENCE > OCEANS > SEA ICE > ICE EDGES
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Direct Numerical Simulations are carried out at the ice ocean interface of 1.8 m long, inclined at angles, 50 degree, 65 degree and 90 degree from the horizontal where external source buoyancy is added as a boundary conditions with relative buoyancy B* 5, 7 and 10 times the wall buoyancy. The data set contains 1. Time averaged temperature, salinity and velocity fields of the flow at steady state where averaging windows are several times the respective buoyancy frequency for 90 degree, B* =1, 5,7,10; 50 degree, B*=1, 5, 7 respectively. 2. Tabulated, time averaged along-slope profiles of a) temperature, b) salinity, c) meltrate, d) plume velocity for 90 degree, B* =1, 5,7,10; 65 degree, B* =1, 5,7,10 and 50 degree, B*=1, 5, 7 respectively. 3. Tabulated, domain averaged meltrate, plume velocity for 90 degree, B* =1,3, 5,7,10; 65 degree, B* =1,3, 5,7,10 and 50 degree, B*=1,3, 5, 7 respectively.
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Maps of East Antarctic landfast sea-ice extent, generated from approx. 250,000 1 km visible/thermal infrared cloud-free MODIS composite imagery (augmented with AMSR-E 6.25-km sea-ice concentration composite imagery when required). Because of imperfections in the MODIS composite images (typically caused by inaccurate cloud masking, persistent cloud in a given region, and/or a highly dynamic fast-ice edge), automation of the fast-ice extent retrieval process was not possible. Each image was thus classified manually. A study of errors/biases of this process revealed that most images were able to be classified with a 2-sigma accuracy of +/- ~3%. More details are provided in Fraser et al., (2010). *Version 1.2 with extra QC around the Mawson coast and Lutzow-Holm Bay The directory named "pngs" contains browsable maps of fast-ice extent, in the form of Portable Network Graphics (PNG) images. Each of the 159 consecutive images (20-day intervals from Day Of Year (DOY) 61-80, 2000 to DOY 341-366, 2008) contains a map of fast-ice extent along the East Antarctic coast, generated from MODIS and AMSR-E imagery. The colour scale is as follows: Dark blue: Fast ice, as classified from a single 20-day MODIS composite image Red: Fast ice, as classified using the previous or next 20-day MODIS composite images Yellow: Fast ice, as classified using a single 20-day AMSR-E composite image White: Antarctic continent (including ice shelves), as defined using the Mosaic of Antarctica product. Light blue: Southern ocean/pack ice/icebergs These maps are also provided as unformatted binary fast ice images, in the directory named "imgs". These .img files are all flat binary images of dimension 4300 * 425 pixels. The data type is 8-bit byte. Within the .img files, the value for each pixel indicates its cover: 0: Southern Ocean, pack ice or icebergs, corresponding to light blue in the PNG files. 1: Antarctic continent (including ice shelves), as defined using the Mosaic of Antarctica product, corresponding to white in the PNG files. 2: Fast ice, as classified from a single 20-day MODIS composite image, corresponding to dark blue in the PNG files 3: Fast ice, as classified using a single 20-day AMSR-E composite image, corresponding to yellow in the PNG files 4: Fast ice, as classified using the previous or next 20-day MODIS composite images, corresponding to red in the PNG files To assist in georeferencing these data, files containing information on the latitude and longitude of each pixel are provided in the directory named "geo". These files are summarised as follows: lats.img: File containing the latitude of the centre of each pixel. File format is unformatted 32-bit floating point, 4300 * 425 pixels. lons.img: File containing the longitude of the centre of each pixel. File format is unformatted 32-bit floating point, 4300 * 425 pixels. The .gpd Grid Point Descriptor file used to build the projection is also included. It contains parameters which you can use for matching your projection. To refer to the time series, climatology, or maps of average persistence, please reference this paper: Fraser, A. D., R. A. Massom, K. J. Michael, B. K. Galton-Fenzi, and J. L. Lieser, East Antarctic landfast sea ice distribution and variability, 2000-08, Journal of Climate 25, 4, pp. 1137-1156, 2012 In addition, please cite the following reference when describing the process of generating these maps: Fraser, A. D., R. A. Massom, and K. J. Michael, Generation of high-resolution East Antarctic landfast sea-ice maps from cloud-free MODIS satellite composite imagery, Elsevier Remote Sensing of Environment, 114 (12), 2888-2896, doi:10.1016/j.rse.2010.07.006, 2010. To reference the techniques for generating the MODIS composite images, please use the following reference: Fraser, A. D., R. A. Massom, and K. J. Michael, A method for compositing polar MODIS satellite images to remove cloud cover for landfast sea-ice detection, IEEE Transactions on Geoscience and Remote Sensing, 47 (9), pp. 3272-3282, doi:10.1109/TGRS.2009.2019726, 2009. Please contact Alex Fraser (adfraser@utas.edu.au) for further information.
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Locations of ice edges on 18 north-south transects of the BROKE voyage of the Aurora Australis (AA V4 1995/96). Locations determined from direct observations by the seabird observers on board. The fields in this dataset are: Latitude Longitude Ice Conditions Transect
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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
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Imagery of Aurora Australis and sea ice captured by a 'quadcopter' (Inspire) drone launched from the ship
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This dataset contains ice motion observations made under the Australian Antarctic Program, Projects 4593 and 4506. Measurements of ice motion where made on (land)fast ice on the eastern rim of the Amery Ice Shelf, Antarctica (69.2 degr. S, 76.3 degr. E) and on landfast ice in Gronfjorden, Svalbard (78.0 degr. N, 14.2 degr. E). Data was obtained using Spotter wave buoys (Sofar Ocean Technologies), hereafter wave buoys, and open-source ice motion loggers, hereafter ice buoys. Instrumentation was deployed on top of the sea ice with the main motivation to measure its vertical motion due to ocean waves. The wave buoys 3-axis measure motion at 2.5 Hz through GPS and have an accuracy of approximately 2 cm for the significant wave height. The ice buoys measure motion in 9-degrees-of-freedom at 10Hz using a VectorNAV VN-100 IMU, accuracy is O(mm) for short waves and O(cm) for long waves. Both instruments also record their geographical location through GPS. Full time series of their motion is processed on board and summaries are send through Iridium. For the wave buoy, this occurred at an interval of 30 minutes. For the ice buoy this occurred every 3 hours. In the dataset, WB and IB are abbreviations for wave buoy and ice buoy, respectively. This dataset covers 2-8 January 2020 for the Antarctic campaign (WB1, WB2, IB1, IB2) and 14-28 March for the Arctic campaign (IB3, IB4, IB5) and includes significant wave height, peak period and the geographical coordinates of the instrumentation. ‘Hs’ refers to significant wave height (in meters). ‘Tp’ refers to peak period (in seconds). Time is in UTC, and in Matlab’s datenum format (i.e. the number of days since year 0000). The geographical coordinates ‘lat’ and ‘lon’ (latitude and longitude, respectively) are in degrees. Note, as the ice buoys transmit the GPS coordinates and wave data in separate data messages, for the ice buoys ‘time’ refers to the reference time of the wave properties Hs and Tp, whereas ‘time_latlon’ refers to the reference time of the geographical coordinates. For the wave buoy, all data is transmitted in one message.
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The Antarctic Sea ice Processes and Climate [ASPeCt] data sets submitted here have been collected systematically from the bridge of an icebreaker, while it transited through the pack ice. Quantifiable observations of sea ice thickness and related characteristics of the sea ice, snow, ocean and surface atmosphere are recorded hourly while the vessel moves through the sea ice. If the vessel is stopped or has not moved at least 6nm since the previous observation, no observation will be conducted. The observation protocol has been endorsed by the Scientific Commission for Antarctic Research (under their ASPeCt programme) as the preferred method for conducting ship-based observations of sea-ice characteristics. Details can be found in Worby and Allison [1999] The spreadsheet information below is also included in the word document in the download file. The relevant spreadsheets (xls files) contain the following information: Header name Physical parameter Unit Year Year Date Day/Month/Year Julian Day Day of year Time (UT) Time of day in Universal time: Hours/Minutes/Seconds Lat (oN) Latitude oN Lon(oE) oE Conc Total ice concentration Tenth OW Open-water classification See Worby and Allison [1999] c1 Ice concentration of primary ice category Tenth ty1 Ice type of primary ice category See Worby and Allison [1999] iz1 Thickness of primary ice category cm f1 Floe size of primary ice category See Worby and Allison [1999] t1 Topography of primary ice category See Worby and Allison [1999] s1 Snow type on primary ice category See Worby and Allison [1999] sz1 Snow thickness on primary ice category cm c2 Ice concentration of secondary ice category Tenth ty2 Ice type of secondary ice category See Worby and Allison [1999] iz2 Thickness of secondary ice category cm f2 Floe size of secondary ice category See Worby and Allison [1999] t2 Topography of secondary ice category See Worby and Allison [1999] s2 Snow type on secondary ice category See Worby and Allison [1999] sz2 Snow thickness on secondary ice category cm c3 Ice concentration of tertiary ice category Tenth ty3 Ice type of tertiary ice category See Worby and Allison [1999] iz3 Thickness of tertiary ice category cm f3 Floe size of tertiary ice category See Worby and Allison [1999] t3 Topography of tertiary ice category See Worby and Allison [1999] s3 Snow type on tertiary ice category See Worby and Allison [1999] sz3 Snow thickness on tertiary ice category cm Sea Sea-surface temperature oC Air Surface-air temperature oC
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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.