Spread-F at Temperate and High Latitudes

Abstract

Spread-F at temperate and high latitudes has been analysed to study its variation with season, geomagnetic activity, sunspot activity and h'F. It is observed that at low temperate latitudes there is no correlation with geomagnetic activity. At high temperate latitudes spread-F is positively correlated with geomagnetic activity in winter and equinoxes while there is no correlation in summer. At auroral zone spread-F is positively correlated with geomagnetic activity but negatively correlated with sunspot activity. At polar latitudes spread-F occurrence is more than that in the auroral zone and there is no correlation with geomagnetic activity. The h'F variation also follows the spread-F variation. The maximum increase on disturbed days in auroral region favours the theory that charged particles are the cause of spread-F at high latitudes.