This dataset is a bathymetric grid of the region 60E to 90E and 48.45S to 70S, created in a geographic coordinate system based on a WGS84 horizontal datum. The grid has a cell size of 0.005 degrees. Most of the work involved creating a bathymetric grid of the region 60E to 90E and 55S to 70S which was generated from the latest available multibeam swath bathymetry, fisheries' surveys and satellite altimetry data. A report outlining the development of this grid is available for download (see the related url below). This grid was then merged with the bathymetric grid described by the metadata record 'Bathymetric Grid of Heard Island - Kerguelen Plateau Region (2005)', which covers the region 68E to 80E and 48S to 56S. Hence the final grid has two 'No data' areas between 48.45S to 55S: 60E to 68E and 80E to 90E. The final grid is available for download as a geotiff and ArcInfo ascii file and contours derived from the grid are available for download as a shapefile (see the related urls below).

Bathymetry data was collected using a Simrad EK60 echosounder. The sample data have been corrected for the relative locations of GPS antenna, transducers and waterline. A sound-speed value of 1500 m/s was applied when calculating depth. The seafloor depth itself was defined firstly as the depth of the sounder-detected bottom minus 10m (contact Simrad for more information about their bottom-detection algorithm), and then modified manually where necessary to ensure that the line followed the seafloor as perceived by eye from the echogram. This is therefore a subjective process, and the true seafloor depth may vary from the perceived depth by several hundred metres in the worst cases. The greatest uncertainties are typically at greater depths, e.g. greater than 1000 m. This seafloor depth line therefore refers to the approximate depth (not range from transducer) of the seafloor less 10 m, i.e. 10 m should be added to the 'depth' values in the *.CSV file to give the 'true' seafloor depth. Depths greater than 5000 m are not available due to the 12 kHz data not being logged any deeper than this. These data are preliminary and subject to change. Bathymetry data was exported during the voyage by Belinda Ronai. Post voyage enquiries however should be directed to Toby Jarvis.

Acoustic sounder charts were collected at six locations during Australian Antarctic Division Voyage 6 1994/95 (BANGSS) using the Kongsberg EA200 Echo Sounder on the Aurora Australis. BANGSS is an acronym for Big ANtarctic Geological and Seismic Survey. The voyage began on 6 February 1995 and finished on 12 April 1995. Each chart is labelled with information about when and where the data was collected: date, time, latitude and longitude. The charts provide a profile of the sea floor and have a time axis with numbers in the following format. the first two digits are the day the next two digits are the month the next five digits are the time (UTC) the last ten digits are the maximum value on the depth axis eg 2402005 360000000500 means 24 February 5:36 UTC and the maximum value on the depth axis is 500 metres See a Related URL for a link to information about the voyage including the voyage report.

Readme - Bathymetry Files Data for BROKE-WEST 2006 1) Zipped folder contains .csv files created from each acoustics ev file for Transects 1 to 11. 2) These files contain subsections of each transect of variable length (usually between 50 and 100 km). 3) No data exists for files; Transect01_01 and 01_02 as the sea floor was greater than 5000m deep in these areas and was below the range set for the sounder. 4) Each file contains 11 columns of data; Ping_date, Ping_time, Ping_milliseconds, Latitude, Longitude, Position_status, Depth, Line_Status, Ping_status, Altitude, GPS_UTC time. 5) For practical purposes, the columns of interest will be Ping_date, Ping_time, Latitude, Longitude and Depth. Other columns are ancillary acoustics information and can be ignored. Line status should be 1 (meaning good) as sea floor was only picked when it could be easily defined. If the sea floor could not be visually defined or was deemed to uncertain, it was not picked in the echogram. Hence sea floor may not be totally contiguous. 6) Depth of the sea floor was only defined for those areas deemed to be 'on transect', i.e. straight transects for acoustics survey purposes. Deviations from the transect, i.e. to pick up moorings, conduct target or routine trawls or visit nice looking bergs were deemed 'off transect' and were excluded from the analysis. 7) Sea floor depth was primarly defined for the purposes of the acoustics analysis, i.e. exclusion from the echograms. Hence the values in the files are for the 'sea floor exclusion line' that is set above the true sea floor in order to exclude noise from the analysis. This means the sea floor depths in these files are likely to be an underestimate of the true depth. The uncertainty is likely to be of the order of 2 to 10m. 8) Another source of error is that depth was calculated with values of absorption coefficient and sound speed set to default values derived from pre-cruise hydrographic data. One value for each parameter was applied to the whole data set. These values were; 0.028 dB/m (120 KhZ), 0.010 dB/m (38kHz), 0.041 dB/m (200 kHz), 0.0017 dB/m (12kHz - bathy sounder) for absorption coefficient and 1456 m/s for sound speed. 9) These values will be recalculated from the oceanographic data derived during the voyage and applied to the data set during post-processing (forthcoming analyses for May-June 2006). Revision of these parameters may cause a slight shift in the calculated depths, although this is likely to be small. 10) Reprocessing of the data may also result in more accurate bottom detection. This data should be available post June 2006 and will be sent to interested parties as soon as it is completed. 11) Dataset was created by Esmee van Wijk.

---- Public Summary from Project ---- This project is designed to provide an understanding of the interactions between krill, other zooplankton, the physical environment and the predators dependent on krill. This will directly address a number of pressing problems facing CCAMLR (the Commission for the Conservation of Antarctic Marine Living Resources) in its attempts to manage the krill fishery using an 'ecosystem approach'. Expected outcomes: As a result of logistic operations (i.e. diversion to Casey) the 29 days on site allocated to this work was reduced to 10 days. Hence only a fraction of the intended program of work was conducted. Acoustics: Acoustics data (for 38, 120, 200kHz) was collected for the top 250m of the water column for nine and a half of the planned 13 transects in our 60 x 60 nautical mile survey region.

The Australian Antarctic Division (AAD) has been collecting hydroacoustic data from its ocean going vessels for a number of years. This collection represents all hydroacoustic data gathered since 1990. The data are stored on the AAD Storage Area Network (SAN), and as such are only directly accessible by AAD personnel. Currently a very large volume of data are stored (greater than 2 TB), hence distribution of these data are logistically feasible really only for people with access to the SAN. As well as data, a large amount of documentation is provided - including methods used to collect these data, as well as any products resulting from these data (e.g. papers, reports, etc). In the past, these data have been collected under several ASAC projects, ASAC 357 (Hydroacoustic Determination of the Abundance and Distribution of Krill in the Region of Prydz Bay, Antarctica) and ASAC 1250 (Krill flux, acoustic methodology and penguin foraging - an integrated study) - ASAC_357 and ASAC_1250. As of 2019-12-19 the folders present in the acoustics data directory are: 1990-05_Aurora-Australis_HIMS 1991-01_Aurora-Australis_AAMBER2 1991-10_Aurora-Australis_WOCE91 1992-01_Aurora-Australis_Calibration_Great-Taylors-Bay 1993-01_Aurora-Australis_Calibration_Port-Arthur 1993-01_Aurora-Australis_KROCK 1993-02_Aurora-Australis_Calibration_Mawson 1993-03_Aurora-Australis_WOES-WORSE 1993-08_Aurora-Australis_Calibration_Port-Arthur 1993-08_Aurora-Australis_THIRST 1994-01_Aurora-Australis_SHAM 1994-12_Aurora-Australis_WOCET 1995-02_Aurora-Australis_Calibration_Casey 1995-07_Aurora-Australis_HI-HO_HI-HO 1996-01_Aurora-Australis_BROKE 1996-01_Aurora-Australis_Calibration_Port-Arthur 1996-02_Aurora-Australis_Calibration_Casey 1996-08_Aurora-Australis_WASTE 1997-01_Aurora-Australis_BRAD 1997-09_Aurora-Australis_ON-ICE 1997-09_Aurora-Australis_WANDER 1997-11_Aurora-Australis_SEXY 1997-11_Aurora-Australis_V3 1997-98-050_V5 1998-02_Aurora-Australis_SNARK 1998-04_Aurora-Australis_PICCIES 1998-07_Aurora-Australis_FIRE-and-ICE 1998-09_Aurora-Australis_V2 1998-10_Aurora-Australis_SEXYII 1999-01_Aurora-Australis_V5 1999-03_Aurora-Australis_STAY 1999-07_Aurora-Australis_Calibration_Port-Arthur 1999-07_Aurora-Australis_IDIOTS 1999-10_Aurora-Australis_V2 1999-11_Aurora-Australis_V4 2000-01_Aurora-Australis_V5 2000-02_Aurora-Australis_V6 2000-10_Aurora-Australis_Calibration_Port-Arthur 2000-11_Aurora-Australis_V1 2000-12_Aurora-Australis_KACTAS 2001-01_Aurora-Australis_Calibration_Mawson 2001-02_Aurora-Australis_Calibration_Davis 2001-10_Aurora-Australis_CLIVAR 2002-01_Aurora-Australis_LOSS 2002-09_Aurora-Australis_V1 2002-10_Aurora-Australis_Calibration_Port-Arthur 2003-01_Aurora-Australis_KAOS 2003-02_Aurora-Australis_Calibration_Mawson 2003-03_Aurora-Australis_Off-charter 2003-09_Aurora-Australis_ARISE 2003-09_Aurora-Australis_Calibration_NW-Bay 2003-11_Aurora-Australis_V2 2003-12_Aurora-Australis_HIPPIES 2004-02_Aurora-Australis_V7 2004-05_AAD_Lab-testing 2004-06_Aurora-Australis_Off-charter 2004-10 2004-10_Aurora-Australis_Calibration_NW-Bay 2004-10_Aurora-Australis_V1 2004-11_Aurora-Australis_V2 2004-11_Howard-Burton_NW-Bay-testing 2004-12_Aurora-Australis_ORCKA 2004-12_Howard-Burton_NW-Bay-testing 2005-02_Aurora-Australis_V5 2005-04_Howard-Burton_Bruny-Island-testing 2005-11_Aurora-Australis_Calibration_Port-Arthur 2005-11_Aurora-Australis_V2 2006-01_Aurora-Australis_BROKE-West 2006-02_Aurora-Australis_Calibration_Mawson 2006-03_Aurora-Australis_V5 2006-09_Aurora-Australis_V1 2006-12_Aurora-Australis_V2 2007-01_Aurora-Australis_SAZ-SENSE 2007-04_Aurora-Australis_V5 2007-08_Aurora-Australis_SIPEX 2011_10_20_Aurora_Calibration 200910_Aurora-Australis_BathymetryProcessing 201803_tankExperiments 20150102_Tangaroa 200708030_Aurora-Australis_V3_CEAMARC 200708040_Aurora-Australis_V4 200708060_Aurora-Australis_V6_CASO 200809000_Aurora-Australis_VTrials 200809010_Aurora-Australis_V1 200809020_Aurora-Australis_V2 200809030_Aurora-Australis_V3 200809050_Aurora-Australis_V5 200910000_Aurora-Australis_VTrials 200910010_Aurora-Australis_V1 200910020_Aurora-Australis_V2 200910030_Aurora-Australis_V3 200910040_Aurora-Australis_V4 200910050_Aurora-Australis_V5 200910070_Aurora-Australis_VE1 201011000_Aurora-Australis_VTrials 201011002_Aurora-Australis_VE2 201011010_Aurora-Australis_V1 201011020_Aurora-Australis_V2 201011021_Aurora-Australis_VMS 201011030_Aurora-Australis_V3 201011040_Aurora-Australis_V4 201011050_Aurora-Australis_V5 201112000_Aurora-Australis_VTrials 201112001_Aurora-Australis_VE1 201112010_Aurora-Australis_V1 201112020_Aurora-Australis_V2 201112030_Aurora-Australis_V3 201112040_Aurora-Australis_V4 201112050_Aurora-Australis_V5 201112060_Aurora-Australis_V6 201213000_Aurora-Australis_VTrials 201213001_Aurora-Australis_VMS_SIPEX 201213010_Aurora-Australis_V1 201213020_Aurora-Australis_V2 201213020_Aurora-Australis_V3 201213040_Aurora-Australis_V4 201314010_Aurora-Australis_V1 201314020_Aurora-Australis_V2 201314040_Aurora-Australis_V4 201314060_Aurora-Australis_V6 201415000_AuroraAustralis-Trials 201415010-AuroraAustralis_V1 201415020_AuroraAustralis_V2 201415030_AuroraAustralis_V3 201415040_AuroraAustralis_V4 201516000-AuroraAustralis_VTrials 201516010_AuroraAustralis_V1 201516020_AuroraAustralis_V2 201516030-AuroraAustralis_V3 201617010-AuroraAustralis_V1 201617020-AuroraAustralis_V2 201617030-AuroraAustralis_V3 201617040-AuroraAustralis_V4 201718010-AuroraAustralis_V1 201718020-AuroraAustralis_V2 201718030-AuroraAustralis_V3 201718040-AuroraAustralis_V4 201819010-AuroraAustralis_V1 201819020-AuroraAustralis_V2 201819030-AuroraAustralis_V3 201819040-AuroraAustralis_V4 201920000-AuroraAustralis_VTrials 201920010-AuroraAustralis_V1 201920011-AuroraAustralis_VMI