Riometer Data Format

ASWFC holds Riometer data from four stations (abbreviated as follows):

• Casey (cas)
• Davis (dav)
• Macquarie Island (mcq)
• Mawson (maw)

Original riometer data are stored in daily binary files. Before being made available on the ASWFC website and data server they are converted to text files and gzipped. Each riometer file name starts with ri followed by year, month and day, with a file name extension comprising the station abbreviation (followed by .gz").

For example, ri080301.cas.gz is a gzipped Riometer data text file for 1 March 2008 from Casey station.

The first line of each file is a short description of the file. This is followed by data lines, one for each 10 seconds. These lines each have six fields space-separated fields:

• hour
• minute
• second
• Raw (DU)
• QDC (DU)
• Absorption (dB)

In these riometer data sets, DU stands for digital units. The analog riometer output is converted to digital data at the point of data collection (ie, at the station). The conversion process involves adding an analog offset (-5V) to put the riometer signal near the middle of the A to D dynamic range (+/- 5v), applying a gain of x2, then converting to a signed 12-bit digital value. The possible range of digital values is then +/- 2047 bits, or DU.

The following example represents a part of the riometer file ri080301.cas.gz.