Radial data files contain radial components of sea surface parameters measured by HF ocean radars operated by 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 ACORN 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 ACORN 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 ACORN to assign a quality control label.