Аскаплоты полярных сияний за 1971 г. / Рос. акад. наук, Кол. науч. центр, Поляр. геофиз. ин-т. – Апатиты : Кольский научный центр РАН, 1997. - 68 с.

that within a given half-an-hour interval the aurora was observed within the scale o f zenith angles from 60 N to 80 N. The second black square corresponds to aurora in the zenith (from 60 N to 60 S) and the third black square marks aurora in the South (from 60 S to 80 S). Occurrence o f auroras in the corresponding part o f the sky was marked when an aurora was observed during at least one minute in a given time interval. Suppose the height o f the lower edge o f aurorae is about 100 km we get all three angle intervals at about 3 degrees o f corrected geomagnetic latitude. Presence o f stars on the films makes it possible to guess meteorological conditions in every latitude interval. Acco'rding to /1 ,2 / the dot in the middle o f the square shows weak clouds o r partial clouds in the given part o f the sky. The vertical line denoted ten- tenths cloud. The tick inside the square o f the third line points to bad quality o f the ascafilm caused by some technical reasons. The horizontal line denotes absence o f observations. To mark moon lighting the horizontal line was used over the ascaplot. Two bottom lines o f squares infonn about auroral activity. The first black squares mean index 2 auroral activity and the two black bottom squares refer to that o f index 3 aurorae. It should be noted that the activity in ascaplots does not entirely coincide with brightness o f forms. The index o f activity also includes such parameters as the type o f the form and its life-time within the given half-an-hour interval. Auroral activity has been estimated only for the zenith region. Series o f auroral activity published in / 6 / were taken as a basis. They are connected with the peculiarities o f substorm development and, to some extend, characterise intensity o f the substorm. 8