Аскаплоты советских станций за 1980 год : (оперативно-информационный материал) / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : Кольский филиал АН СССР, 1984.

I I осcuring simultaneously the Index ie calculated by the moat Important form plus 1. For example( if during more than 15 min a weak homogeneous arc (HA.) and a weak radiant band (RB) were observed in the вку, the index equals to: 6 (radiant band) + 1 (occurence of another form) * 7 that corresponds to the third ball of auroral activity. One ie added for a quich motion of the main auroral form. For example, a bright quickly moving radiant band existing leas than 15 min with ooourence of other foxms gives: 7 (bright radiant band) + 1 (its quick motion) + 1 (occureno.e of other auroral forme) « 9 . Figure 1 shows that a very bright homogeneous arc observed during the whole interval (half an hour) gives 2 balls, whereas a mere fact of appearance of a corona corresponds to the same activity. Such estimation of aurora activity in balls is connected with peculiarities of development of the auroral substorm. According to /10/ the periods of no disturbance or absolutely quiet periods homogeneous arcs (HA) and bands (HB) with brightness gaining sometimes 2 balls (theee are not the balls of activity but the balls of brightness acording to International Classific ation) may be observed along the compressed oval. On the dayside separate rays or weak radiant arcs are usually seen. A weak subatorm brings increasing of bright ness, appearance of curves, i.e. transition of arcs into bands and appearance of radiant struoture. A strong substorm is characterized by an apparent breakup, i.e. quick motion of aurorae, collapse Of forms, appearance of coronae and pulsating aurorae. Thus, the aeries of aurora activity used for ascaplotting is connected with the peculiarities of substorm development and to some extend, characterizes intensity of the subatorm. Figure 2 presents an example of ascaplote. The numerals I-XV show various possible situations. In the given example the camera did not operate until 13,10 UT. Observations began at 13.30 UT, aurorae were obaent, cloudiness with rente was in the north and in the zenith (I). During the next half-an-hour interval (II) aurorae were absent also, complete cloudiness was in the north and in the zenith, cloudiness with rents was in the south; III and IV corresponds to the time intervals of complete cloudiness covering all the sky; V denotes cloudi ness with rents in the south and in the zenith, and no clouds in the north. Aurorae in the north appeared at 16 UX (VI), there were no clouds in the zenith and. cloudiness with rents in the south. VII shows no clouds in the sky, aurorae were observed in the north and in the zenith. VIII marks that the sky was clear, aurorae were only in the north, local geomagnetio midnight. IX shows that aurorae again shifted to the zenith and their activity gained 2 balls, no clouds in the south. Xi aurorae spread all over the sky, the activity in the zenith wasequal to 3 balls. XIi aurorae were in the north and in the zenith, activity of 3 balls, neither aurorae no clouds in the south. XIIi no aurorae were observed in the north, probably because of cloudiness with rents, the activity in the zenith reduced to 2 balls. XIIIt aurorae of not more tban 1 ball were observed in the north and in the zenith, no clouds in the south. XIVi the sky is oloudless, no aurorae, moon lighting, XV» the situation is similar, but the asoafilms due to technical reasons (bad development of this part of the film, breaks of automatic work) turned out to be of low quality. The described example presents all situations one may encounter in asoaplots.