Radial data files contain radial components of sea surface parameters measured by HF ocean radars operated by Ocean Radar (formerly known as the Australian Coastal Ocean Radar Network (ACORN)), a facility of Integrated Marine Observing System (IMOS). Regardless of the radar system (WERA or SeaSonde), the primary product is the radial component of the sea surface current along a line between the radar station and a point on the sea surface. By combining radials measured at two stations surface current vectors can be constructed. These surface current vectors can then be used to study tides, wind-driven currents and perform lagrangian particle tracking. Raw data collected at each radar site are re-processed by the facility in order to assign quality control flags to data points. This is not possible in real-time because real-time data are produced by proprietary manufacturer software without quality control flags and it is not feasible to transfer the raw data to the facility in real-time. Each radial file contains a set of standard metadata fields, such as radar system type, operating frequency and bandwidth. Other metadata fields describe radar system type-specific parameters. Radial file metadata fields are described in a separate Ocean Radar data document. In addition, for WERA radar systems, the facility provides quality controlled heights of left and right bragg peaks, from which the wind direction can be inferred.

Radial data files contain radial components of sea surface parameters measured by HF ocean radars operated by Ocean Radar (formerly known as the Australian Coastal Ocean Radar Network (ACORN)), a facility of Integrated Marine Observing System (IMOS). Regardless of the radar system (WERA or SeaSonde), the primary product is the radial component of the sea surface current along a line between the radar station and a point on the sea surface. By combining radials measured at two stations surface current vectors can be constructed. These surface current vectors can then be used to study tides, wind-driven currents and perform lagrangian particle tracking. A snap-shot of the radial surface current map is produced by a radar station every 10 min (WERA) or 1 h (SeaSonde). These data are uploaded to the IMOS archive in real-time. Real-time data are produced by the manufacturer of the radar station and no quality control flags are assigned by either the manufacturer or the facility at this stage. Each real-time radial file contains a set of standard metadata fields, such as radar system type, operating frequency and bandwidth. Other metadata fields describe radar system type-specific parameters. Radial file metadata fields are described in a separate facility data document. In addition, WERA radar systems provide the real-time heights of left and right bragg peaks, from which the wind direction can be inferred, and an estimate of the significant wave height. These quantities are not quality controlled because they are output from the manufacturer's software without the detail necessary for the facility to assign a quality control label.

Coastal ocean surface radar is a land-based technique which uses scattering from the rough sea surface to obtain echoes which are Doppler shifted by the dynamics of the sea. It has been shown (Crombie, 1955) that the scatter is predominantly a Bragg interaction between the radio wave and the sea surface gravity wave that is propagating in the same direction and with half the wavelength of the radio wave. This Bragg interaction gives two strong first-order lines in the echo spectrum; one from the resonant gravity wave moving radially away from the station, and one from the resonant gravity wave moving towards the station. Phased array systems determine the azimuthal angle between the station and a point on the sea surface by forming a narrow beam; the range to the point is set by the propagation delay for the electromagnetic wave. For the phased array systems, the two radar stations each operate for alternating periods of 5 minutes on and 5 minutes off, and out of phase, so that they can use the same frequency without interfering with each other. During each 5 minute of operation the radar measures the component of the surface current at each point projected onto the radial from the station to the point. At the end of 10 minutes, the radial components of surface currents can be combined from the two stations to find the vector at each position on the grid. While surface currents are generally the data of most interest, the phased array systems can also produce significant wave heights and wind directions at each grid point and a calculation of the full directional wave spectrum at ranges of up to about half the maximum range (which is 150 km). WERA HF ocean radar systems are used in the Capricorn Bunker Group (Tannum Sands and Lady Elliot Island), Queensland, at South Australian Gulf (Cape Spencer and Cape Wiles), South Australia, for Rottnest Shelf (Fremantle and Guilderton), Western Australia, and at Coffs Harbour (Red Rock and North Nambucca), New South Wales.

The Tannum Sands (TAN) HF ocean radar site (-23.942 S, 151.371 E) is one of two HF ocean radars covering Heron Island in the Capricorn Bunker Group (CBG) in the southern region of the Great Barrier Reef Marine Park World Heritage Area. The other HF ocean radar station is at Lady Elliot Island. The HF ocean radar coverage is from the coast to beyond the edge of the continental shelf. The TAN HF ocean radar is a WERA phased array system with a 12-element receive array. This radar operates at a frequency of 8.348 MHz, with a bandwidth of 33 KHz and a maximum range of 200 Km and a range resolution of 4.5 Km. Azimuthally the radar covers a sweep 45 deg either side of a bore sight direction of 47 deg true east of north (approximately north-east). Within the HF radar coverage area surface current radials are measured. Data are also collected from which wind directions and significant wave height can be calculated. This station was decommissioned in April 2017.

The Red Head (RHED) HF ocean radar site (33.010245 S 151.727059 E) is one of two HF ocean radars covering the Newcastle area, New South Wales. The other HF ocean radar station is at Seal Rocks. The HF ocean radar coverage is from the coast to beyond the edge of the continental shelf. The RHED HF ocean radar is a SeaSonde crossed-loop direction finding array. This radar operates at a frequency of 5.2625 MHz, with a bandwidth of 25 KHz, a maximum range of 200 Km and a range resolution of 6 Km. Within the HF radar coverage area surface current radials are measured.

The Seal Rocks (SEAL) HF ocean radar site (32.441575 S 152.539022 E) is one of two HF ocean radars covering the Newcastle area, New South Wales. The other HF ocean radar station is at Red Head. The HF ocean radar coverage is from the coast to beyond the edge of the continental shelf. The SEAL HF ocean radar is a SeaSonde crossed-loop direction finding array. This radar operates at a frequency of 5.2625 MHz, with a bandwidth of 25 KHz, a maximum range of 200 Km and a range resolution of 6 Km. Within the HF radar coverage area surface current radials are measured.

The Nora Creina (NOCR) HF ocean radar site (37.329 S 139.850 E) is one of two HF ocean radars covering the Bonney Coast, South Australia. The other HF ocean radar station is at Blackfellows Cave. The HF ocean radar coverage is from the coast to beyond the edge of the continental shelf. The NOCR HF ocean radar is a SeaSonde crossed-loop direction finding array. This radar operates at a frequency of 5.211 MHz, with a bandwidth of 50 KHz, a maximum range of 200 Km and a range resolution of 3 Km. The antenna bearing is 255 deg true east of north (approximately west by south-west). Within the HF radar coverage area surface current radials are measured. This station was decommissioned in March 2017.

The Fremantle (FRE) HF ocean radar site (32.031 S, 115.746 E) is one of two HF ocean radars covering Rottnest Shelf and Perth Canyon off the coast north of Perth. The other HF ocean radar station is at Guilderton. The HF ocean radar coverage is from the coast to beyond the edge of the continental shelf. The FRE HF ocean radar is a WERA phased array system with a 16-element receive array. This radar operates at a frequency of 8.512 MHz, with a bandwidth of 33 KHz, a maximum range of 200 Km and a range resolution of 4.5 Km. Azimuthally the radar covers a sweep 60 deg either side of a bore sight direction of 285 deg true east of north (approximately west by north-west). Within the HF radar coverage area surface current radials are measured. Data are also collected from which wind directions and significant wave height can be calculated.

SOFS is an observing platform in the Sub-Antarctic Zone, approximately 350 nautical miles southwest of Tasmania. It obtains frequent measurements of the surface and deep ocean properties that control the transfer of heat, moisture, energy and CO2 between the atmosphere and the upper ocean to improve understanding of climate and carbon processes. The mooring was first deployed at (46.7S, 142E) in March 2010 and recovered in April 2011. It was re-deployed in November 2011 at (46.8S, 142E) and recovered in July 2012, it was then re-deployed in August 2012 at (-46.7S, 142E) and recovered in January 2013, it was then re-deployed in May 2013 at (-46.8S, 142E) and recovered in October 2013. The mooring was redeployed in March 2015. The SOFS is equiped with two identical ASIMET systems and telemetry to provide real time data to marine observers and researchers.

The Cervantes (CRVT) HF ocean radar site (30.506 S 115.060E) is one of two HF ocean radars covering Rottnest Shelf and Perth Canyon on the Turquoise Coast north of Perth. The other HF ocean radar station is at Seabird. The HF ocean radar coverage is from the coast to beyond the edge of the continental shelf. The CRVT HF ocean radar is a SeaSonde crossed-loop direction finding array. This radar operates at a frequency of 5.211 MHz, with a bandwidth of 50 KHz, a maximum range of 200 Km and a range resolution of 3 Km. The antenna bearing is 288 deg true east of north (approximately west by north-west). Within the HF radar coverage area surface current radials are measured.