Vertical velocity of the water column (currents)

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  • This dataset consists of model outputs from ensemble simulations of an idealised Southern Ocean using a quasi-geotrophic model called Q-GCM. As such, there are no calendar dates associated with it. Two models were generated: Initial Condition Perturbation Ensemble (ICPE) experiments model output covers years 162-168 of the simulation; Boundary Condition Perturbation Ensemble (BCPE) experiments model output covers years 150-180 of the simulation. The models created form the practical element of the NERC project ‘The structure and stability of transport and fixing barriers within the Antarctic Circumpolar Current’. The project aims to quantify the relationship between Southern Ocean winds, the eddy saturation mechanism and the branch-like structure of the Antarctic Circumpolar Current. The work was funded by means of a Natural Environment Research Council (NERC) Discovery Science New Investigators Grant ‘NE/I001794/1’. The grant ran from 02 August 2010 to 21 September 2012 and was led by Dr. Chris Wilson at the UK’s National Oceanography Centre (NOC). The model simulation data were submitted to the British Oceanographic Data Centre (BODC) for archive and are stored in the originator format.

  • This multi-decadal time series initially contains water current and temperature data from a single, near bottom instrument. A second, shallower instrument recording the same parameters was subsequently added after several years of successful operation. Conductivity data are similarly integrated into the time series after a further period of operation. The data are typically at hourly resolution. The mooring is situated in the Tiree Passage, between the Isles of Mull and Coll, off the west coast of Scotland. The specific site chosen was where the passage is at its narrowest (10 km), mid-way between the coasts of the two Isles. The mooring site is in water depths of approximately 45 m. Mooring activity began in June 1981 and consisted of a single RCM current meter placed 11 m above the seabed. The mooring design was modified to incorporate a second RCM current meter at 22 m above the seabed from November 1987. Aanderaa conductivity sensors were added at the two depths in 1993, with MicroCAT conductivity sensors being incorporated in 2002. There are some gaps in the record, most noticeably between January 2000 and May 2002, a period when the observations were temporarily suspended. Fishing damage has generated smaller gaps in the data set over the years. This region was chosen as a site for long term monitoring after radiocaesium studies showed that the major part of the water carried northwards from the North Channel in the Scottish coastal current passes between Mull and Coll. The mooring provides data for comparison with tracer studies and for an examination of the roles of wind forcing and buoyancy contributions to the coastal current. Tiree Passage mooring work is led by Colin Griffiths at the Scottish Association for Marine Science (SAMS).

  • The dataset comprises current profiles and temperature data from 9 half-day survey cruises in the Pentland Firth during April, June, July and October 2009. The data were collected using an acoustic Doppler current profiler (ADCP) mounted on the Aurora, the Environmental Research Institute (ERI) survey vessel, and have been fully processed and calibrated by Dr Lonneke Goddijn-Murphy from the Environmental Research Institute, University of the Highlands and Islands prior to submission to the British Oceanographic Data Centre (BODC). The circulation patterns of the inner sound, Pentland Firth were studied. The purpose of the study was to improve knowledge and capabilities for understanding wave and tidal renewable energy devices and predicting environmental impacts of renewable energy development. The data are available on request from BODC.

  • The World Ocean Isopycnal-Level Velocity (WOIL-V) climatology was derived from the United States Navy's Generalised Digital Environmental Model (GDEM) temperature and salinity profiles, using the P-Vector Method. The absolute velocity data have the same horizontal resolution and temporal variation (annual, monthly) as GDEM (T, S) fields. These data have an horizontal resolution of 0.5 degrees ×0.5 degrees, and 222 isopycnal-levels (sigma theta levels) from sigma theta = 22.200 to 27.725 (kg m-3) with the increment delta sigma theta = 0.025 (kg m-3), however in the equatorial zone (5 degrees S – 5 degrees N) they are questionable due to the geostrophic balance being the theoretical base for the P-vector inverse method. The GDEM model, which served as the base for the calculations includes data from 1920s onwards and the WOIL-V will be updated with the same frequency as the GDEM. The climatological velocity field on isopycnal surface is dynamically compatible to the GDEM (T, S) fields and provides background ocean currents for oceanographic and climatic studies, especially in ocean isopycnal modeling. The climatology was prepared by the Department of Oceanography, Naval Postgraduate School.

  • This dataset consists of current velocity measurements of the water column from an upward-looking Acoustic Doppler Current Profiler (ADCP) deployed on the seabed and also includes CTD casts from an SBE 911+ CTD taken a long the Wyville Thompson Ridge. The mooring is situated in the region of the Wyville Thomson Ridge – a notable bathymetric feature running north-west from the Scottish shelf towards the Faroe Bank. The gully present between the Ridge and the parallel Ymir Ridge is the study site chosen for mooring work that began in 2003 and ended in 2013. Mooring deployment durations have typically ranged from between five and twelve months. Successive deployments have enabled a multi-year time series to develop. There have, however, been periods of instrumentation loss, which account for some gaps in the overall record (most noticeably during 2008/2009). Servicing of the mooring has been achieved using various research vessels and has often been incorporated into the schedule of the annual cruises occupying the Extended Ellett Line. The mooring consists of an anchored buoy housing an RDI Long Ranger ADCP, designed to rest on the seabed, with the instrument facing upwards. Current velocity measurements from the mooring help to provide valuable insight into regional ocean circulation. A small, poorly quantified, component of the southward-flowing deep water from the Arctic cascades over the Wyville Thomson Ridge from the Faroe Bank Channel into the northern Rockall Trough. Maintaining this time series will afford a better understanding of this outflow. The Wyville Thomson mooring work is led by Toby Sherwin at the Scottish Association for Marine Science (SAMS).

  • 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.

  • This dataset consists of measurements of horizontal and vertical current velocity and of vertical profiles of temperature and salinity collected during cruise PE372 in the Bosphorus Strait and South West Black Sea, June and July 2013 . Pelagia cruise PE372 formed part of the field collection of project "Flow dynamics and sedimentation in an active submarine channel: a process-product approach" which was composed of NERC Discovery Science lead grant NE/F020511/1 and 2 child grants: NE/F020120/1 and NE/F020279/1

  • Rothera Oceanographic and Biological Time Series (RaTS) in Antarctica began in 1997 and involves regular sampling of the water column undertaken by CTD (conductivity, temperature and depth) casts with associated collection of discrete water samples and the deployment of four moorings. The RaTS site is located in Marguerite Bay, approximately 4 km from shore and over a water depth of approximately 520 m. Marguerite Bay is enclosed by Adelaide Island to the north, Alexander Island to the south and the Antarctic Peninsula to the east. When optimal conditions are not available a secondary site is occupied. In times when fast ice prevents sampling at both the primary and secondary site, a third site is utilised close to the Rothera Research Station. However, only a water sample is collected during this time as the water is too shallow to allow for a cast to be conducted. An upper ocean CTD cast is made every five days in the summer and every seven days in the winter, except when weather, ice or logistic constraints intervene. A CTD unit is lowered from an inflatable boat by use of a hand-cranked winch during summer months and through a hole in the ice during the winter. As well as conductivity, temperature and depth other variables measured from the CTD cast include fluorescence and down-welling irradiance. Measurements are typically binned to 1 metre increments with a varying maximum depth typically ranging between 200 and 500 metres. Subsequent data processing involves the calculation of salinity from the conductivity channel (applying the UNESCO 1983 algorithm), calculation of chlorophyll from raw fluorescence and calibration, plus calculating depth from the pressure output. Discrete water samples are taken from a depth of 15 m using a Niskin bottle closed with a brass messenger. Water samples collected are measured for macronutrients (nitrate, nitrite, phosphate, ammonia and silicate), chlorophyll (both whole and size fractionated), dissolved oxygen isotopes, dissolved organic carbon and microbial community analysis. There are two extended periods during which no data could be collected. August to December, in both 2000 and 2001. In 2000, there was an unusually extended period of unfavourable ice conditions which were too heavy for boat operations and unsafe for sledge operations. Then in the period during 2001 a fire occurred which resulted in loss of use of the laboratory at Rothera. It was not possible to restart observations until replacement equipment arrived with the relief of the Rothera Research Station the following December. The mooring deployments took place in January 2005 (13 months), February 2006 (10 months) and December 2006 (4 months). A further mooring was deployed in the Marguerite trough in January 2005 for approximately 13 months. Mooring instrumentation included current meters, acoustic Doppler current profilers (ADCP), temperature and depth recorders, a CTD and a sediment trap. These sensors were strung out from the surface down to approximately 390 m (sediment trap). Data was collected in 15 minute intervals from the ADCP and once every hour from all the other sensors. Data processing included calibration of the pressure, conductivity and pressure channels and calculation of salinity (from conductivity channel) and depth (from pressure channel). This time series is continuously monitored by the British Antarctic Survey in an attempt to gain a suite of oceanographic data which provide an environmental background to aid interpretation of the near-shore marine ecology and to test a series of broad hypothesis concerned with pelagic-benthic coupling and environmental forcing of the near-shore oceanographic environment. The project has previously been managed by Prof. Andrew Clarke and Prof. Mike Meredith. At present (November 2021), the project and dataset is directed and managed by Mr. Hugh Venables of the British Antarctic Survey and data are available on request from the British Oceanographic Data Centre.

  • The RAPID-WATCH (Rapid Climate Change - Will the Atlantic Thermohaline Circulation Halt?) data set consists of pressure, current velocities, temperature, salinity and density time series. Measurements are collected by moored instruments deployed in arrays across the Atlantic at approximately 26.5N for the Monitoring the Atlantic Meridional Overturning Circulation at 26.5N (MOC) project and at each of three sections across the US and Canadian continental slope between Cape Cod and the Grand Banks for the Western Atlantic Variability Experiment (WAVE) project. The data set also consists of conductivity- temperature-depth (CTD) profiles, and ships' underway monitoring system meteorology and surface hydrography collected during the mooring deployment and servicing cruises. The RAPID-WATCH data set follows on from the original Rapid Climate Change (RAPID) Programme oceanographic dataset (2004-2008). It spans from 2008 until 2015. The RAPID-AMOC data set is expected to extend the RAPID_WATCH dataset to 2020. The main aims of the RAPID-WATCH Programme are to provide oceanographic measurements that allow a decade-long time series of the Atlantic Meridional Overturning Circulation to be derived for use in climate change research. The MOC project is led by scientists at the National Oceanography Centre in Southampton, whilst work on the WAVE element is led by the Liverpool site of the National Oceanography Centre.

  • 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.