Electrical conductivity of the water column
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For around a decade, southern elephant seals (mirounga leonina) have been used to collect hydrographic (temperature & salinity) profiles in the Southern Ocean. CTD-SRDLs (Conductivity Temperature Depth –Satellite Relayed Data Loggers) attached to seals' heads in Antarctic and sub-Antarctic locations measure water property profiles during dives and transmit data using the ARGOS (Advanced Research & Global Observation Satellite) network (Fedak 2013). CTD-SRDLs are built by the Sea Mammal Research Unit (SMRU, University of St Andrews, UK); they include miniaturised CTD units made by Valeport Ltd. When seals are foraging at sea 2.5 profiles can be obtained daily, on average. Profiles average 500m depth, but can be 2000m in extreme cases (Boehme et al. 2009, Roquet et al. 2011). Deployment efforts have been very intensive in the Southern Indian Ocean, with biannual campaigns in the Kerguelen Islands since 2004 and many deployments in Davis and Casey Antarctic stations (Roquet et al., 2013) more recently. 207 CTD-SRDL tags have been deployed there, giving about 75,000 hydrographic profiles in the Kerguelen Plateau area. About two thirds of the dataset was obtained between 2011 & 2013 as a consequence of intensive Australian Antarctic station deployments. There is also regular data since 2004 from French and Franco-Australian Kerguelen Island deployments. Although not included here, many CTD-SRDL tags deployed in the Kerguelen Islands included a fluorimeter. Fluorescence profiles can be used as a proxy for chlorophyll content (Guinet et al. 2013, Blain et al. 2013). Seal-derived hydrographic data have been used successfully to improve understanding of elephant seal foraging strategies and their success (Biuw et al., 2007, Bailleul, 2007). They provide detailed hydrographic observations in places and seasons with virtually no other data sources (Roquet et al. 2009, Ohshima et al. 2013, Roquet et al. 2013). Hydrographic data available in this dataset were edited using an Argo-inspired procedure and then visually. Each CTD-SRDL dataset was adjusted using several delayed-mode techniques, including a temperature offset correction and a linear-in-pressure salinity correction - described in Roquet et al. (2011). Adjusted hydrographic data have estimated accuracies of about +/-0.03oC and +/-0.05 psu (practical salinity unit). The salinity accuracy depends largely on the distribution of CTD data for any given CTD-SRDL, which decides the quality of adjustment parameters. Adjustments are best when hydrographic profiles are available in the region between the Southern Antarctic Circumpolar Current Front and the Antarctic divergence (55oS-62oS latitude range in the Southern Indian Ocean). Several institutes provided funding for the associated programs and the logistics necessary for the fieldwork. The observatory MEMO (Mammifères Echantillonneurs du Milieu Marin), funded by CNRS institutes (INSU and INEE), carried out the French contribution to the study. The project received financial and logistical support from CNES (TOSCA program), the Institut Paul-Emile Victor (IPEV), the Total Foundation and ANR. MEMO is associated with the Coriolis centre, part of the SOERE consortium CTD02 (Coriolis-temps différé Observations Océaniques, PI: G. Reverdin), which distributes real-time and delayed-mode products. The Australian contribution came from the Australian Animal Tracking and Monitoring System, an Integrated Marine Observing System (IMOS) facility. The work was also supported by the Australian Government's Cooperative Research Centres Programme via the Antarctic Climate & Ecosystem Cooperative Research Centre. The University of Tasmania and Macquarie University's Animal Ethics Committees approved the animal handling. Both tagging programs are part of the MEOP (Marine Mammals Exploring the Oceans Pole to Pole) international consortium - an International Polar Year (IPY) project.
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The North Atlantic Norwegian Sea Exchange (NANSEN) data set comprises hydrographic profiles (temperature and salinity) and time series of current velocity, temperature and occasionally conductivity from the North Atlantic Ocean. The measurements were collected between 1986 and 1988 using conductivity-temperature-depth (CTD) profilers, moored current meters and thermistor chains. Data collection was undertaken by six laboratories in four countries (Faroes, Germany, Norway and the UK). The NANSEN project was conceived by the International Council for the Exploration of the Sea (ICES) Oceanic Hydrography Working Group. It aimed to study the hydrography and circulation of the Iceland Basin and the temporal and spatial variability of the inflows and outflows across the Greenland-Scotland Ridge. Current meter data from a number of laboratories involved in NANSEN and CTD data collected by UK participants are managed by the British Oceanographic Data Centre (BODC). A further 50 current meter series have been collected, but have not yet been acquired by BODC. The data will be subjected to the usual BODC quality control procedures for current meter series. The hydrographic data set collected during the NANSEN experiment has been compiled by the ICES Secretariat.
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The dataset comprises of vertical profiles of water column properties (temperature, salinity, conductivity, pressure, depth, sound velocity and density) of the full water column in the South West region of the UK. Measurements were taken opportunistically at three main locations (L4, L5 and E1 Western Channel Observatory stations) as well from Plymouth Sound and the surrounding inshore areas. Data have been gathered using a Valeport MIDAS 606 CTD (with a passive flow induction cell, Platinum Resistance Thermometer and a strain gauge transducer) and extracted and processed using Valeport DataLogX2 software (version1.0.4.1270). The CTD was deployed using vertical deployment from the RV MBA Sepia and were hauled using a manually controlled hydraulic winch. The surveyors have been dependent on the sensor calibrations applied by the CTD manufacturer (Valeport). Manufacturer calibrations are applied to the in situ direct measurements via sensor specific microchips in the CTD unit. Derived parameters are calculated using the in-built processing provided with the units software: Datalogx2. The data have been collected in the framework of the long term monitoring of the Western Channel Observatory stations and the Plymouth inshore fisheries undertaken annually by the Marine Biological Association of the United Kingdom. The RV MBA Sepia department of the Institute carried out the data collection activities.
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The data set comprises more than 7000 time series of ocean currents from moored instruments. The records contain horizontal current speed and direction and often concurrent temperature data. They may also contain vertical velocities, pressure and conductivity data. The majority of data originate from the continental shelf seas around the British Isles (for example, the North Sea, Irish Sea, Celtic Sea) and the North Atlantic. Measurements are also available for the South Atlantic, Indian, Arctic and Southern Oceans and the Mediterranean Sea. Data collection commenced in 1967 and is currently ongoing. Sampling intervals normally vary between 5 and 60 minutes. Current meter deployments are typically 2-8 weeks duration in shelf areas but up to 6-12 months in the open ocean. About 25 per cent of the data come from water depths of greater than 200m. The data are processed and stored by the British Oceanographic Data Centre (BODC) and a computerised inventory is available online. Data are quality controlled prior to loading to the databank. Data cycles are visually inspected by means of a sophisticated screening software package. Data from current meters on the same mooring or adjacent moorings can be overplotted and the data can also be displayed as time series or scatter plots. Series header information accompanying the data is checked and documentation compiled detailing data collection and processing methods.
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The dataset comprises 12 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the Inner Seas off the West Coast of Scotland area specifically Loch Kishorn, Loch Alsh, Loch Duich, Loch Hourn, Loch Nevis, Loch Sunart and the Sound of Sleat. Data were collected during January 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 Fisheries Research Services Aberdeen Marine Laboratory.
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The dataset comprises hydrographic measurements including current velocity, temperature, salinity and sea level data. Results of one iodine experiment are also included. The data were collected in the area of the Faroe Islands, Shetland, the Norwegian Sea and the Barents Sea between May 2000 and November 2001 over a series of 31 cruises using the research vessels Scotia (UK), Magnus Heinason (Faroes), Johan Hjort and G.O.Sars (Norway). Measurements included five repeated conductivity-temperature-depth (CTD) sections in the Faroe Shetland Channel, North of Faroes, Gimsøy and Svinøy and Fugløya - Bear Island. Fifty one moorings containing current meters, acoustic Doppler current profilers (ADCPs), bottom pressure recorders and inverted echosounders were deployed along the sections. Ten RAFOS floats were also deployed in the Lofoten Basin to measure Lagrangian currents. During the Johan Hjort cruise in May 2000 about 300 water samples were collected in order to measure 129Iodine concentration (relative to 127I). Analysis was carried out by the Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, France. Observational data from the standard tidal stations at Tórshavn, Lerwick, Bodø and Ny-Ålesund were also used in the analysis. The main objective of MAIA was the development of an inexpensive, reliable system for monitoring the inflow of Atlantic water to the northern seas, based on coastal sea-level data. The project involved contributions from a number of international institutions. The resulting data set was collated at BODC and published on CD-ROM in March 2003.
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The dataset comprises 64 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, taken at each trawling station from the Inner Seas off the west coast of Scotland, Irish Sea and St. George's Channel, and the North East Atlantic Ocean (limit 40W) areas including the specific locations: north and west coasts of Scotland; Irish Sea West Orkney; Butt of Lewis; Outer Hebrides; Inner Hebrides; South Minch; Clyde; North & West Ireland, Irish Sea. CTD casts taken during the month of March 2004. 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 Fisheries Research Services Aberdeen Marine Laboratory.
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The dataset comprises 71 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the North Sea area specifically around the Firth of Forth, Wee Bankie and Marr Bank areas, during June and July of 2000. 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 Fisheries Research Services Aberdeen Marine Laboratory.
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The dataset comprises 48 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the North Sea area specifically around Orkney and Shetland, during June of 1990. 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 Scottish Office Agriculture and Fisheries Department Aberdeen Marine Laboratory.
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The dataset comprises 41 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the North Sea and the North East Atlantic Ocean (limit 40W) areas specifically the north western North Sea, north of Scotland, during July of 2000. 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 Fisheries Research Services Aberdeen Marine Laboratory.