The data set comprises acoustic and associated environmental data from multi-parameter underwater acoustic experiments undertaken in the Gulf of Lions, N.W. Mediterranean and Loch Ness, Scotland. Measurements were made over the period 30 January 1995 to 22 September 1995. Of primary interest were shallow water (10-200m), medium range (1-10km) channels at communication frequencies in the 10-100kHz range. Modulation techniques used include: Carrier Wave, ASK, PSK, FSK, Multi-ASK, Multi-PSK and Multi-FSK. Multi-parameter underwater acoustic experiments were carried out under high level control and in total more than 36 Gigabytes of acoustic and associated environmental data were gathered. Experiments were carried out at medium depth (50-100m) in the Gulf of Lions and deeper water (50-200m) in Loch Ness, and the data were stored on a series of CD-ROMs. A suite of tests was performed over set ranges (1km, 7km, etc.). In general, each range was contained on a set of three CD-ROMs which specifically referred to individual parameters set for that particular range (e.g. location, gain levels, projector and hydrophone depths). Alongside the data recordings, the IRIG 'B' time signal was also recorded during all experiments to allow derivation of precise timings of all signal transmissions and receptions. This information is also contained on the CD-ROMs. Associated environmental parameters were recorded and documented. These data were collected using CTD profilers, thermistor chains, tide gauges, current flow meters and an ORETECH Weatherpak-400. The raw data were logged in an ASCII format on a DAT cartridge. The primary aim of EEVMAC (European Experimentally Validated Models for Acoustic Channels) was the generation of signals and the recording of data for propagation model validation in connection with the characterisation of underwater acoustic channels. Data were collected by researchers from Heriot-Watt University, UK and the Laboratoire de Physique et Chimie Marines (LPCM), France. The British Oceanographic Data Centre holds 19 Gigabytes of edited data on CD-ROM, along with copies of the raw environmental data. Further details on the environmental data can be sought from Laboratoire d’Oceanographie de Villefranche, formerly LPCM.

This dataset consists of optical and acoustic seabed profiles of near bed hydrodynamics, bed morphology and suspended material in the water. Fieldwork was carried out by a team of researchers over a two week period, 24 May to 04 June 2013, surveying an area near Hilbre Island in the Dee Estuary. Measurements were taken in the inter-tidal and sub-tidal zones. Measurements were collected at three sites within the sampling area. A SEDbed suite of acoustic and optical instruments were deployed at each station to collect data. These instruments included CTD, LISST, Acoustic Doppler Velocimeter, Bedform and suspended sediment imager, Multi-tier sediment trap and 3-D Acoustic Rippler Profiler. The data collection described formed the fieldwork component of the NERC-funded project “Realistic Sedimentary Bedform Prediction: Incorporating Physical and Biological Cohesion (COHBED)”. The project was undertaken with the aim to produce information about the growth, movement and stability of bedforms that consist of natural mixtures of sands and muds. The project was composed of Standard Grant reference NE/I027223/1 as the lead grant with child grants NE/I026863/1, NE/I024402/1, NE/I02478X/1. The lead grant runs from 05 January 2012 to 04 July 2015 and the child grants run from 15 December 2011 to 14 June 2015 (NE/I026863/1), 01 January 2012 to 30 June 2015 (NE/I024402/1), and 01 January 2012 to 31 October 2015 (NE/I02478X/1). Dr Jacobus Hugo Baas of Bangor University, School of Ocean Sciences was the principal investigator of the lead grant of this project. The child grants were led by Dr Sarah Bass of University of Plymouth, School of Engineering, Professor Daniel Roy Parsons of University of Hull, Geography, Environment and Earth Science, and Professor Daniel Paterson of University of St Andrews, Biology, respectively. The data described here have been received as raw files by BODC and will be processed using our in-house systems and made available online in the future.

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).