Keyword

Sound velocity and travel time in the water column

45 record(s)
 
Type of resources
Topics
Keywords
Contact for the resource
Provided by
Years
Representation types
Update frequencies
From 1 - 10 / 45
  • Categories  

    This dataset contains a variety of hydrographic measurements including temperature, salinity, sound velocity, current speed/ direction and seismic data. Hydrographic profilers provided measurements of temperature, salinity, sound velocity and density. Four mooring stations were also installed as part of this project, with three minilogger chains providing temperature data and four moored ADCPs measuring current veloicty. The project ran from February 2006 to September 2009, however all of the data were collected between 17 April 2007 and 14 May 2007 during two cruises which took place in the Gulf of Cadiz. The research was conducted using two research vessels, the RRS Discovery (cruise D318) and the RV Poseidon (cruise PO350). The RRS Discovery cruise D318 was split into two legs, D318a, which took place between 17 April 2007 and 23 April 2007 and D318b, which took place between 29 April 2007 and 14 May 2007. For the second leg of cruise D318, the RRS Discovery was joined by the RV Poseidon. Hydrographic measurements were taken using a variety of instruments, including expendable bathythermographs (XBT), expendable CTDs (XCTD), conductivity-temperature depth (CTD) profilers, acoustic doppler current profilers (ADCP) and VEMCO minilogger chains. Airguns and streamers were used in the recording of the seismic data. The main objectives of the Geophysical Oceanography (GO) project were A) To evaluate and improve new research methods in the developing field of seismic oceanography by exploiting the opportunity of two-ship operations between RSS Discovery and RV Poseidon and B) To study the internal wave field and mixing processes in the Gulf of Cadiz and demonstrate quantitative links between seismic and oceanographic measurements. The cruise was coordinated by Durham Univerity and funded under an EU grant as part of the Framework 6 NEST programme. Eight scientific institutions were involved in the project. These were: the University of Durham, the Proudman Oceanographic Laboratory (POL), the Helmholtz Centre for Ocean Research Kiel (IFM-GEOMAR), the French Research Institute for Exploitation of the Sea (IFREMER), the Italian National Agency for New Technologies, the Energy and Sustainable Economic Development (ENEA), the Spanish National Research Council (CSIC), the University of Western Brittany and the University of Lisbon. Data from the programme are held at the British Oceanographic Data Centre.

  • Categories  

    The data set comprises measurements of water temperature, salinity, current velocities and sound velocity, and sediment characteristics. The data were collected in the Clyde Sea in July and August 1997. The bulk of the measurements were made at the acoustic transmission point Tx1 (55 31.6N, 4 49.7W), and at receiving points SW of Tx1 up to 20 km away. In addition a SW-NE section (55 13.5N, 5 9.4W to 55 35.0N, 4 46.3W) was sampled at the beginning and end of the experiment, and a W-E section (5 3.0W to 4 52.7W at 55 31.6N) was run three times during the experiment. The data were collected by the research vessels Prince Madog and Calanus. Throughout the experiment the Prince Madog was used to deploy the acoustic transmission equipment, and as the main oceanographic vessel. The Calanus acted as the receiving ship, and also collected conductivity-temperature-depth (CTD) profiles. Overall, 199 CTD casts, 71 hours of temperature time series data, 150 hours of acoustic Doppler current profiler (ADCP) data, 70 hours of RoxAnn (sidescan sonar), position and water depth data, and three sediment sound speed profiles were collected. Two CTDs were used onboard the Prince Madog: a Seabird SBE-19 and a Neil Brown Mk. III. A Neil Brown SmartCTD was used on the Calanus. Several casts were made onboard the Madog with both CTDs attached to the same frame for intercalibration purposes. At the bottom of each cast with the Neil Brown Mk. III CTD two SIS digital reversing thermometers were triggered and a seawater sample collected, which was later analysed in the laboratory for salinity. Temperature and salinity data from the Madog CTDs were calibrated using these values. No seawater samples were collected by the Calanus. Data from all CTDs were despiked and spurious density inversions were removed. The majority of the CTD casts were repeat casts at either the acoustic transmission or reception point, the object being to monitor the high frequency variability of the water column, and allow model predictions of the acoustic signal characteristics to be tested against observed signal variations. Whilst the Prince Madog was on station at Tx1 four internally recording temperature sensors were deployed at fixed depths. During some overnight runs a single temperature/depth sensor was also deployed; during transmission experiments this sensor was attached to the acoustic source. The ADCP onboard the Madog was used to record vertical current profiles for most of the experiment. A RoxAnn system onboard the Prince Madog was used during part of the experiment to log ship position, water depth, and the bottom roughness and hardness indices E1 and E2. Three bottom sediment cores were collected on 5/8/97 with a hydroplastic (gravity) corer. Two metre core barrels with an internal diameter of about 8cm were used. The cores each contained between 1m and 1.5m of sediment, and were analysed for sound speed at the University of Wales, Bangor after the cruise. The cores were taken at Tx1 (55.527N, 4.832W), 10 km (55.441N, 4.843W), and 20 km (55.371N, 4.880W) along the primary acoustic track. The precision of the sound speed measurements is +/- 10 m/s. The PROSIM Clyde Sea experiment was primarily an acoustic transmission experiment designed to study shallow water acoustic propagation. The oceanographic data were collected to provide information on the mean and time-varying characteristics of the water column for use in acoustic modelling. PROSIM was undertaken by the Unit for Coastal and Estuarine Studies, a self-funded research unit attached to the School of Ocean Sciences, University of Wales, Bangor. The unit specialises in physical oceanography and ocean modelling. The data are stored at the British Oceanographic Data Centre (BODC).

  • Categories  

    This dataset consists of measurements of water column structure including hydrographic profiles, temperature and salinity, turbulence data, turbidity and fluorescence profiles, current velocities and sound velocities. The measurements were undertaken during a comprehensive survey of the southern Celtic Sea between May and August 2012. Some turbulence microstructure data were collected from the 14th to the 24th of May 2012, while the remaining data were collected from the 10th to the 22nd of August 2012, with the use of the RV Falcon Spirit. These cruises formed the field component of NERC Discovery Science project "Assessing the sensitivity of marginally stratified shelf seas within a changing climate". The data were collected in order to identify processes involved in the existence and intensity of the front displays not governed by tidal periodicities, to test whether the processes identified as important to changes in shelf sea stratification through in-situ measurements are indeed responsible for observed changes and to incorporate knew knowledge into state of the art numerical models that can up-scale the processes observed within this project to the shelf sea environment. The Discovery Science project was composed of Standard Grant reference NE/I001832/1. The project ran from 01 January 2011 to 30 June 2014. Dr Philip Hosegood of University of Plymouth School of Marine Science and Engineering was the principal investigator of this project. The moored temperature logger data have been received by BODC as raw files from the RV Falcon Spirit, processed and quality controlled using in-house BODC procedures and can be downloaded on-line from the BODC website in a variety of data formats including ASCII, ODV and NetCDF. Full documentation on the dataset is supplied on download. Raw file versions of the minibat towed undulator transect data, moored ADCP data, VMADCP data and turbulence microstructure data are available on request.

  • Categories  

    The 26 North dataset comprises moored temperature, conductivity and salinity, current velocity, acoustic travel time and bottom pressure time series. Data have been collected in the North Atlantic between latitudes of 23.7 degrees N and 28 degrees N in three sub -arrays at the Western Boundary (76.9 degrees W to 69.4 degrees W), Mid-Atlantic Ridge (52.1 degrees W to 40.9 degrees W) and Eastern Boundary (24.2 degrees W to 12.2 degrees W ). A number of instrumented moorings, some of which are full depth, have been deployed in each sub-array. Data have been collected since February 2004 and the moorings have been turned around every year. Data have been collected using a variety of moored instrumentation including conductivity-temperature-depth (CTD) sensors, current meters, Bottom Pressure Recorders (BPR), Inverted Echo Sounders (IES) and Acoustic Doppler current profilers (ADCPs). Data are collected in order to calculate and continuously monitor the Meridional Overturning Circulation (MOC) and provide a long term time series of the strength of the MOC. The 26 North dataset comprises moored data collected by the RAPID: monitoring the Atlantic Meridional Overturning Circulation at 26.5 degrees N since 2004 (RAPIDMOC) project and the Meridional Overturning Circulation and Heat-flux Array (MOCHA) project. Data are held at the British Oceanographic Data Centre.

  • Categories  

    This dataset consists of measurements of density, electrical conductivity, sound velocity and travel time, salinity, depth and temperature of the water column. The data were acquired from the RV Falcon Spirit, the Plymouth University vessel. The small 14m catamaran was used on a daily basis from 13 May 2012 to 24 May 2012 in the Celtic Sea, off the Cornish coast, with the idea to capture high-quality, spatially-resolved field data ahead of the Wave Hub construction. Measurements were collected using CTDs, moored temperature loggers, ADCP, VMADCP and towed minibat CTD. These cruises formed the field component of NERC Discovery Science project "Wave Hub baseline study". The aims of the research were to obtain a detailed oceanographic study at the Wave Hub site and surrounds - covering the whole range of physical, chemical and biological parameters before the deployment of Wave Hub infrastructure and wave energy devices – and to ensure data acquisition in time and space to allow development of physical and ecosystem models at scales relevant to wave arrays. Ultimately models will make predictive assessments of the extent, timescales and intensity of ecosystem impacts and perturbation resulting from implementation of wave energy arrays. Other aims include: engagement of environmental economists to ensure the data can be used to develop economic valuation estimates of critical life-supporting ecosystem services at scales appropriate to arrays of wave devices for comparison with other uses of marine space and to address questions that have arisen directly in respect of marine renewable energy development and sustainable use of marine resources. The Discovery Science project was composed of Standard Grant reference NE/I015094/1 as the lead grant with child grants NE/I015183/1 and NE/I015108/1. The lead grant, NE/I015094/1, ran from 01 August 2010 to 31 July 2012, with Dr Ricardo Javier Torres, Plymouth Marine Laboratory, as principal investigator. The child grant NE/I015183/1 ran from 01 August 2010 to 31 July 2011, led by Professor Michael Richard Belmont, University of Exeter. The second child grant, NE/I015108/1, ran from 03 December 2010 to 31 July 2012, led by Dr Philip John Hosegood, University of Plymouth. All data detailed here were received by BODC as raw files from the RV Falcon, processed and quality controlled using in-house BODC procedures. Towed undulator CTD data and temperature logger data have been processed to completion and are available online on the BODC website. The remaining data will be made available in the near future.

  • Categories  

    The data set comprises of geophysical observations in the source regions of the 2004 and 2005 great Sumatra earthquakes. Geophysical surveys were carried out to determine the seabed bathymetry and underlying structure and geometry and included the collection of seismic reflection, magnetic, gravity, and sidescan sonar data. In addition, Conductivity-Temperature-Depth (CTD) and Sound-Velocity Probe (SVP) data were collected, as well as continuous meteorological (air pressure, air temperature, radiance, relative humidity, wind direction and speed) and sea surface (temperature and conductivity) data. Data were collected in the Indian Ocean, west and north west of Sumatra between 8 degrees South, 6 degrees North, 94 and 108 degrees East. The data were collected during three cruises, SO198-1, SO198-2 and SO200 over two legs SO200-1 and SO200-2. The three cruises took place between May 2008 and February 2009. The data collection focussed on the areas around two earthquake segment boundaries: Segment Boundary 1 (SB1) between the 2004 and 2005 ruptures at Simeulue Island, and Segment Boundary 2 (SB2) between the 2005 and smaller 1935 ruptures between Nias and the Batu Islands. Measurements were taken using a variety of instrumentation across all three cruises including: the long-term deployment of 50 Ocean-Bottom Seismometers (OBS) deployed on cruise SO198-1 and retrieved on cruise SO200-1; 154 Expendable Bathythermograph (XBT) probes; high resolution multichannel seismic reflection (MCS) profilers; Swath bathymetric and backscatter echosounders; SVPs and CTDs which were deployed simultaneously; and a gravity meter and Parasound sub-bottom profiler were operated continuously within the survey areas. In addition, sea surface and meteorological measurements were made using the underway system throughout the three cruises, although there are no data for days at the beginning and end of the cruises of up to 10 days. During the two legs of SO200 additional instrumentation was deployed including: a 30 kHz deep-towed sidescan sonar system (TOBI); piston cores and megacores collected along the plate margin; and heatflow probes long transects. The UK Sumatra Consortium project aimed to characterise the subduction boundary between the Indian-Australian plate and the Burman and Sumatra blocks (including subduction zone structure and rock physical properties), record seismic activity, improve and link earthquake slip distribution to the structure of the subduction zone and to determine the sedimentological record of great earthquakes (both recent and historic) along this part of the plate margin. The project will allow better assessment of future earthquake magnitudes and locations, and further the general understanding of the earthquake rupture process. The UK Sumatra Consortium project was led by the National Oceanography Centre Southampton (NOCS) and involved five UK partners; NOCS, the universities of Cambridge, Oxford and Liverpool, and the British Geological Survey as well as numerous international partners including French, German, American, Indonesian and Indian Collaborators. The principal investigator was Dr Timothy Henstock from NOC. The Natural Environment Research Council (NERC) funded data will be managed by the British Oceanographic Data Centre (BODC).

  • Categories  

    The dataset comprises 59 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the English Channel area specifically the western English Channel, during June and July of 2003. A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory.

  • Categories  

    The dataset comprises 56 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the North Sea area including specifically the Dogger Bank (just north), the Thames, Humber, the Wash and off Tyne/Tees. The data were collected during January of 2001. A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the Centre for Environment, Fisheries and Aquaculture Science Lowestoft Laboratory.

  • Categories  

    The Carbon Uptake and Seasonal Traits in Antarctic Remineralisation Depth (CUSTARD) data set comprises hydrographic data, including measurements of temperature, salinity and currents, complemented by bathymetric, meteorological and nutrient data. All the observational data from the project were collected at, and south of, the Ocean Observatories Initiative (OOI) Global Southern Ocean Array, located south-west of Chile. Data collection activities span from November 2018 to January 2020 over 3 cruises (DY096, DY111 and DY112). The main aim of the CUSTARD project is to quantify the seasonal drivers of carbon fluxes in a region of the Southern Ocean upper limb, and estimate how long different quantities of carbon are kept out of the atmosphere based on the water flow routes at the observed remineralisation depths. The lead grant was funded by the NERC grant reference NE/P021247/1 with child grants NE/P021328/1, NE/P021336/1, NE/P021263/1. NE/P021247/1 was held at the National Oceanography Centre, led by Adrian Martin. Child grants were lead by Mark Moore of University of Southampton, Simon Ussher of University of Plymouth and Dorothee Bakker of University of East Anglia respectively.

  • Categories  

    This dataset consists of measurements of underway meteorology, navigation and sea surface hydrography as well as underway discrete salinity samples. A comprehensive survey of the Tropical Atlantic was undertaken between June and August 2017. Data were collected on RRS James Cook cruise JC150. Navigation data were collected using an Applanix POSMV system and meteorology and sea surface hydrography were collected using the NMF Surfmet system. Both systems were run through the duration of the cruise, excepting times for cleaning, entering and leaving port, and while alongside. 65 salinity samples were taken from the non-toxic underway supply. The non-toxic, pumped seawater supply intake was located 5.5 m below the sea surface. Sample analysis was completed using a Guildline ‘Autosal’ salinometer. This cruise formed the field component of NERC Discovery Science project "Zinc, Iron and Phosphorus co-Limitation in the Ocean (ZIPLOc)". The data were collected in order to determine the prevalence of zinc and iron limitation of APA in the phosphate deplete subtropical North Atlantic Ocean; to quantify the impact of zinc-phosphorous and iron phosphorous co-limitation on biological activity, specifically phytoplankton growth, primary production and nitrogen fixation; and to quantify the significance of zonc-phosphorous and iron-phosphorous co-limitation in driving phytoplankton productivity over basin scales and multi-decadal time scales. The Discovery Science project was composed of Standard Grant reference NE/N001079/1 as the lead grant with child grant NE/N001125/1. The lead grant runs from 02 January 2017 to 03 February 2017 and the child grant runs from 01 February 2017 to 31 July 2019. Dr Claire Mahaffey of University of Liverpool, Earth, Ocean and Ecological Sciences was the principal investigator of the lead grant of this project. Prof Maeve C. Lohan of University of Southampton, School of Ocean and Earth Science was the principal investigator of the child grant. The underway discrete salinity samples data and the underway navigation, meteorology and sea surface hydrography data have been received by BODC as raw files from the RRS James Cook, processed and quality controlled using in-house BODC procedures and are will be made available online in the near future.