ADCP
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Metadata record for data from ASAC Project 2720 See the link below for public details on this project. The overall objective is to characterise Southern Ocean marine ecosystems, their influence on carbon dioxide exchange with the atmosphere and the deep ocean, and their sensitivity to past and future global change including climate warming, ocean stratification, and ocean ... acidification from anthropogenic CO2 emissions. In particular we plan to take advantage of naturally-occurring, persistent, zonal variations in Southern Ocean primary production and biomass in the Australian Sector to investigate the effects of iron addition from natural sources, and CO2 addition from anthropogenic sources, on Southern Ocean plankton communities of differing initial structure and composition. These samples were collected on the SAZ-SENSE scientific voyage of the Australian Antarctic Program (Voyage 3 of the Aurora Australis, 2006-2007 season). SAZ-SENSE VOYAGE AU0703 ADCP DATA * The complete ADCP data for cruise au0703 are in the files: au070301.cny (ascii format) a0703dop.mat (matlab format) * The "on station" ADCP data (specifically, the data for which the ship speed was less than or equal to 0.35 m/s) are in the files: au0703_slow35.cny (ascii format) a0703dop_slow35.mat (matlab format) * The file bindep.dat shows the water depths (in metres) that correspond to the centre of each vertical bin. * The data are 30 minute averages. Each 30 minute averaging period starts from the time indicated. (so, e.g., an ensemble with time 120000 is the average from 120000 to 123000). * ADCP currents are absolute - i.e. ship's motion has been subtracted out. * Note that the top few bins can have bad data from water dragged along by the ship. * Beware of data when the ship is underway - it's often suspect. * Important data quality information can be found in the data report referenced above. * The figure a0703difship30.eps shows the speed difference between vertical bin 2 and all other bins, where the data have been divided up into different speed classes for ship speed. The apparent vertical shear for bins ~1-10, and below bin ~40, is an error, possibly due to acoustic ringing from an air/water interface in the seachest. Data where ship speed is 0 to 1 m/s does not show this error.
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A 600KHz Teledyne RDI Workhorse Sentinel ADCP was deployed through a 10inch auger hole, flush with the base of the ice, looking downwards. At ice stations 2, 3, and 4 the deployment locations was Ridge site 1, the ridge site closest to the ship. At ice station 7 there were 4 different deployment locations: - Transducer Hole A, by active ridge on 6th October 2012; - Trace Metal / Bio Site; - 100m Core site of ice-physics transect; - Transducer Hole A, re-drilled on 7th October 2012. Length of deployment varies from stations to station and was limited by AUV operations, when our ADCP was switched off. Files contain the data collected in raw format. This format can be read by Teledyne WinSC software. Data files are stored in folders by ice station (see below).
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Oceanographic measurements conducted on voyage 7 of the Aurora Australis of the 2002-2003 season. These data are ADCP (Acoustic Doppler Current Profiler) data. These data were collected/collated by Mark Rosenberg. Final ADCP data for voyage au0201 (SAZ mooring turnaround and iceberg B9B experiment), Aurora Australis Voyage 1 2002/2003, 17th Oct 2002 to 18th Nov 2002. * The complete ADCP data for cruise au0201 are in the file: au020101.cny (ascii format) a0201dop.mat (matlab format) * The "on station" ADCP data (specifically, the data for which the ship speed was less than or equal to 0.35 m/s) are in the files: au0201_slow35.cny (ascii format) a0201dop_slow35.mat (matlab format) * The file bindep.dat shows the water depths (in metres) that correspond to the centre of each vertical bin. * The data are 30 minute averages. Each 30 minute averageing period starts from the time indicated. (so, e.g., an ensemble with time 120000 is the average from 120000 to 123000). * ADCP currents are absolute - i.e. ship's motion has been subtracted out. * Note that the top few bins can have bad data from water dragged along by the ship. * Beware of data when the ship is underway - it's often suspect. MATLAB VECTORS AND MATRICES: ============================ header info ----------- for header info: column number corresponds to 30 minute average number botd = mean bottom depth (m) over the 30 minute period cnav = GPS info: don't worry about it cruise = cruise number date = ddmmyy (UTC) ibcover = a bottom track parameter: don't worry about it icover = percentage of 30 minute averageing period covered by acceptable 3 minute ensembles lastgd = deepest accepted bin in this profile lat = mean latitude over the 30 minute period (decimal degrees) lon = mean longitude over the 30 minute period (decimal degrees) nbins = no. of bins logged (=60) shipspeed = scalar resultant of shipu and shipv shipu = ship's E/W velocity over the ground over 30 minute period (m/s, +ve east) shipv = ship's N/S velocity over the ground over 30 minute period (m/s, +ve north) time = hhmmss, time (UTC) at start of 30 minute averageing period dectime = time in decimal days from start of year 2002 (e.g. midday on January 2nd = 1.5000) adcp data --------- for adcp data matrices: row number corresponds to bin number column number corresponds to 30 min. average no. bindep = depth (m) to centre of each bin in the profile (will be the same for all profiles) ipcok = percentage of the profile period for which there was good data in this bin (N.B. data=NaN when ipcok=0) qc = a quality control value for each bin - see below speed = scalar resultant of u and v u = east/west current (m/s, +ve east) v = north/south current (m/s, +ve north) ASCII FORMAT FILE: ================== * The file starts with a 3 line header. * Then comes each 30 min. ensemble, as follows: First, a 1 line header, containing date (UTC) (dd-mmm-yyyy) time (UTC) (hh:mm:ss) % of 30 min average covered by acceptable 3 min. ensembles deepest accepted bin in the profile ship's E/W velocity over the ground over the 30min (m/s) ship's N/S velocity over the ground over the 30min (m/s) P= GPS position-derived velocity (D=direct GPS vel.; B=bottom track vel.) mean longitude over the 30 min. mean latitude over the 30 min. % of interfix period for which there was bottom depth information mean bottom depth over the 30 min. 0 0 Next, the data, from the shallowest bin to the deepest bin: for each bin, there's 4 parameters: u = east/west current (m/s, +ve east) v = north/south current (m/s, +ve north) qc = quality control value - see below ipcok = percentage of the profile period for which there was good data in this bin Note that the data are written left to right across each line, then onto the next line, etc. (so 4 bins on a full line) quality control value: ---------------------- qc = %good / (Verr+0.05) where: %good = percent good pings after logging system screening Verr = RMS error velocity (m/s). Possible range of qc is 0-20, with an expected range of 0-10; values of 0-4 indicate very poor data; values above 8 indicate very good data.
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The Lowered Acoustic Doppler Current Profiler (LADCP) data were acquired while the Conductivity Temperature Depth (CTD) sensor was in the water during the Australian 2006 V3 BROKE-west survey. Data Acquisition: The LADCP is mounted on the CTD frame and is lowered through the water column from surface to bottom on each CTD cast. During the cast upward and downward facing sensor heads ensonify the water column with four beams per head, collecting the data necessary to calculate the vertical velocity of the LADCP on the CTD frame, as well as the northward and eastward components of the current relative to the LADCP for the entire water column. Once the LADCP has been retrieved, the data collected in the cast are downloaded to a PC as two raw binary .adp files, one for the upward looking head and one for the downward. This occurs for each CTD cast. The only modification to a normal CTD cast procedure for the LADCP is a 5 minute pause within 50 m of the sea floor on the upcast. This gives the downward sensor time to gather enough data for later determination of relative bottom velocity. The shipboard ADCP is a continuous recording device that operates over the duration of the voyage, ensonifying the water column once a second. It operates in a similar way to the LADCP, except that as it is fixed to the ship, it has only a range of approximately 250m deep. The ADCP data are necessary for final LADCP data processing. Similarly shipboard 10 seconds GPS records and CTD pressure data for the period of each cast is required for LADCP data processing. Data Processing: Once collected the upward and downward raw .adp LADCP files are subjected to fairly extensive processing using software written for the Matlab package, to produce the usable .mat data files given by this dataset. This software, written by Sergeui Sokolov (sergeui.sokolov AT csiro.au), and slightly modified for the 2005/06 V3 BROKE-west voyage by Andrew Meijers and Andreas Klocker combines the raw .adp files with the shipboard ADCP data, 10 second ship GPS data and CTD profile data. While the raw LADCP .adp files can be processed alone with minimal CTD data (date, start time, end time, start and end lat and long and max depth), they will only give current velocities relative to the CTDs frames motion. To gain an absolute profile the software identifies bottom and surface reflections, and uses this and ship ADCP and GPS data as boundary conditions for an integration of the velocity shear in the raw .adp files. The end result of processing is velocity in north and south components for each depth over the CTD cast. For more details refer to the above reference (Wijffels, et. al. 2005). Dataset format: The processed LADCP file (AU0603_LADCP_3_to_120.mat) is given in matlab .mat format, and before future processing with properly calibrated ADCP data, should be regarded as preliminary only. All CTD casts for BROKE-West are included, except for casts 1,2 and 119, where the LADCP was not used in the CTD cast. Casts 1 and 2 are not in the dataset, while 119 is represented by NaN (not a number) values. The absence of casts 1 and 2 from the data mean that care should be taken in attributing the data to the correct cast. Column one in each velocity matrix represents cast 3, not 1, and column 2 is cast 4 and so on up to column 118 representing CTD cast 120. On several casts the ADCP data were not available, meaning only part of the LADCP processing could be completed. This occurred for casts 5, 46, 91, 92, and 96, and data given here are unreferenced to a bottom velocity or ship track. Other errors occurred that meant that casts 68 and 115 could not be processed at all, and so data for these casts are represented by NaN values. Casts not present in dataset: 1,2 Casts represented by NaN values: 68,115 and 119 LADCP data created without ADCP input on casts: 5,46,91,92,96 (warning unconstrained values) The matlab variables contained in the file are: bindep: 20 depth levels in meters at which velocity data occurs for each profile. Each row of matrix represents a depth level, each column a CTD cast, ascending from cast 3 to 120. date: Start date of each cast (UT) (year month day) lat: Start latitude of each cast (decimal degrees) lon: Start longitude of each cast (decimal degrees) stationno: Last 3 digits gives the CTD cast number time: Start time of CTD cast (UT) of each cast (hours min sec) u_down: u (eastward) component of velocity in ms-1 for each bindepth and CTD cast, using only downward looking head data u_final: As for u_down but using data from both heads. This is the best estimate of velocity. u_up: As for u_down, but upward looking head data only. v_down: As for u_down, but northward component of velocity v_final: As for u_final, but northward component of velocity v_up: As for u_up, but northward component of velocity zbottom: Bottom depth in meters for each cast (m) Acronyms used: LADCP: Lowered Acoustic Doppler Current Profiler ADCP: Acoustic Doppler Current Profiler CTD: Conductivity Temperature Depth IASOS: Institute of Antarctic and Southern Ocean Studies CSIRO: Commonwealth Scientific and Industrial Research Organisation This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).
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The Acoustic Doppler Current Profiler (ADCP) data were acquired constantly over the duration of the Australian 2006 V3 BROKE-West survey. Data presented here are the results of 1/2 hour integrations of the cruise data from the start of the voyage in Fremantle, Australia, to the start of the return leg just north of Australia's Davis Station in Antarctica (-66.56S, 77.98E). North and eastward components of the current velocity are given for depths up to 300m below the surface along the ship track. Data Acquisition: The shipboard ADCP is a continuous broadband recording device that operates over the duration of the voyage, ensonifying the water column once a second. As the instrument is fixed to the ship, it has a range of approximately 250m deep. Data from the shipboard Ashtek 3 dimensional GPS system is used along with bottom tracking data (when the water is shallow enough i.e. less than 250m) and automatically integrated into ADCP ping data to provide absolute current velocities. Data Processing: The ship ADCP constantly and automatically collects and stores raw .rawdp binary files in ensembles of three minutes worth of pings. This is regularly automatically collated into larger .adp files containing data for several hours (200+ ensembles). This data are processed for use in analysis using specialist software provided by Mark Rosenberg (mark.rosenberg AT utas.edu.au) that integrates together data from the ADCP .adp files for periods (30 minutes in this case) over a give time (from cruise start to the 3-Mar-2006). This produces .any ASCII files. These ASCII files are read into the Matlab processing package using scripts provided by Sergeui Sokolov (sergeui.sokolov AT csiro.au) which then produces the .mat matlab data files covered by this metadata. ADCP data requires proper calibration with respect to ship motion, which were not carried out for this data set, and could cause significant change when processed properly after the voyage. Dataset format: The processed ADCP file is given in matlab .mat format. All 1/2 hour integrations of ADCP data for BROKE-West from 3 days (31-dec-2005) before departure from Fremantle, to the 3-Mar-2006 are included, each column in each matrix or array representing an individual 1/2 hour integration in chronological order. There are numerous gaps in the data that occurred when the ADCP crashed and was not immediately reset or when bad data prevented processing. The location can be identified by plotting a scatter plot of longitude vs latitude, and the times by plotting the julian date. The matlab variables contained in the BROKE_West_ADCP.mat file are contained inside the adcp structure: lon: Longitude (decimal degrees) lat: Latitude (decimal degrees) time: Each column gives the year month day and hour of collection of the corresponding columns in the other variables. depth: Depth of each corresponding velocity value for each 1/2 profile. 60 fixed bin depths are given for each profile. (meters) press: As for depth but given in db. (db) u: Absolute current eastward component in ms-1 for each depth and profile. v: Absolute current northward component in ms-1 for each depth and profile. unav: Ship absolute eastward component in ms-1 for each profile vnav: Ship absolute northward component in ms-1 for each profile jtime: Julian date for each profile (julian days) badvals: Indexes of anomolous latitude and longitude values Acronyms used: ADCP: Accoustic Doppler Current Profiler IASOS: Institute of Antarctic and Southern Ocean Studies CSIRO: Commonwealth Scientific and Industrial Research Organisation This work was completed as part of ASAC projects 2655 and 2679 (ASAC_2655, ASAC_2679).
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Amery Ice Shelf AM06 borehole drilled early January 2010. Sub-shelf water profiling measurements conducted over a period of a few days. Partial video recording of borehole walls and sea floor benthos. Collection of targeted ice core samples. Sediment sample collected from sea floor. Long term monitoring instruments installed (thermistors in ice, 3 x CTD in ocean cavity). This is a parent record - see the child records for further information, and access to the data. Some general readme documents are available for download from the provided URL.
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This data represents the total collection of acoustic, underway and satellite data collected on voyage 2 of the Aurora Australis in the 2003-04 season. For online access to the underway data for voyage 2 2003-04, see its specific metadata record, or the marine science database. The Acoustics data (ADCP) are in SIMRAD EK64 format (binary), and the echoview software is required to read them. The Underway data are in ASCII format. The Satellite Images are in TERASCAN format, and TERASCAN software is required to read them.
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This data represents the total collection of acoustic, underway and satellite data collected on voyage 7 of the Aurora Australis in the 2003-04 season. For online access to the underway data for voyage 7 2003-04, see its specific metadata record, or the marine science database. The Acoustics data (ADCP) are in SIMRAD EK64 format (binary), and the echoview software is required to read them. The Underway data are in ASCII format. The Satellite Images are in TERASCAN format, and TERASCAN software is required to read them.
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This data represents the total collection of acoustic, underway and satellite data collected on voyage 4 of the Aurora Australis in the 2003-04 season. For online access to the underway data for voyage 4 2003-04, see its specific metadata record, or the marine science database. The Acoustics data (ADCP) are in SIMRAD EK64 format (binary), and the echoview software is required to read them. The Underway data are in ASCII format. The Satellite Images are in TERASCAN format, and TERASCAN software is required to read them.
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Oceanographic data were collected on Aurora Australis Voyage 4 2003/2004, from December 2003 to February 2004, and a calibrated data set was created. The oceanographic program on the voyage was a part of the cruise-determining fish survey in the vicinity of Heard Island. A total of 42 CTD vertical profile stations were taken, most to within 5 m of the bottom. Over 450 Niskin bottle samples were collected and analysed on board, for calibration of the CTD conductivity sensors. Nutrient samples were also collected, but not analysed. Near surface current data were collected using a ship mounted ADCP. Data from the array of ship's underway sensors are included in the data set. The data report describes the processing/calibration of the CTD and ADCP data, and gives important details concerning data quality. An offset correction was derived for the underway sea surface temperature and salinity data, by comparison with near surface CTD data. These data form part of the overall dataset for ASAC project 2388 (ASAC_2388).