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

This part of USGS Data Series 781 (Golden, 2019) presents 2-m-resolution acoustic backscatter data for the Offshore of Point Buchon, California, map area. Backscatter data were collected by Fugro Pelagos in 2008 using a combination of 400-kHz Reson 7125, 240-kHz Reson 8101, and 100-kHz Reson 8111 multibeam echosounder systems. The data were post-processed by the California State University Monterey Bay Seafloor Mapping Lab and the University of California Santa Cruz Center for Integrated Spatial Research. The acoustic backscatter data are available as a georeferenced TIFF image. Within the final imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and composition. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones).