2 sites: Gulf of Lions, Mediterranean and Loch Ness, Scotland, United Kingdom

Electrical conductivity of the water column; Vertical velocity of the water column (currents); Acoustic noise in the water column; Salinity of the water column; Horizontal velocity of the water column (currents); Sediment acoustics; Acoustic backscatter in the water column; Temperature of the water column

Sea level recorders; current meters; hydrophones; acoustic backscatter sensors; CTD; thermistor chains

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.

British Oceanographic Data Centre
Joseph Proudman Building 6 Brownlow Street
Liverpool
Merseyside
L3 5DA
United Kingdom