A comparison between the automatic ionogram scaling system ARTIST and the standard manual method

For the first time, data from mid-latitude ionograms as scaled by the computer system ARTIST and by the standard manual method have been compared comprehensively. Differences between these scaled values for foF2 and M(3000)F2, are presented for five periods between 1984 and 1986, a time of low sunspot activity. These two parameters were studied, as they are most important for high-frequency radio communications. The comparisons reveal that, on average, ARTIST provides acceptable data for about 93% of the time. ARTIST is shown to perform less well during the summer, mainly because of the presence of blanketing-type Ez and the proximity of foF2 to foF1. Severe broadcast station interference is another source of major error. On the basis of these comparisons, ARTIST provides a most valuable service in producing real-time data which can be made available to the radio community by means of a dial-in facility. The other parameters scaled by ARTIST have also been studied, but in far less detail, and no statistics were undertaken. However, these limited comparisons seem sufficient to show serious limitations in ARTIST performance, due mainly to the absence of any accuracy qualification. Such limitations are likely to preclude, in the foreseeable future, ARTIST replacement of manual scaling for the data published in monthly bulletins by Slough, United Kingdom ionospheric observatory.