Diurnal & Seasonal Occurrence Patterns of Pc & Pi Pulsations at Choutuppal (Hyderabad), India

221-226Based on a detailed analysis of data covering a period of 3 X 1/2 year from February 1967 to September 1970, the diurnal and seasonal occurrence patterns of different types of pulsations have been studied. The present study indicated that both Pc1 and Pc2 pulsations at this station are mainly nighttime phenomena with a characteristics seasonal variation pattern showing winter maximum for Pc1 and summer maximum for Pc2 pulsations. The Pc3 type shows a double maxima in the diurnal occurrence pattern centered around 0700 and 1300 hrs LT. The Pc4 activity exhibits a sharp morning peak around 0700 hrs LT while Pc5 show two maxima around 0000 and 0900 hrs LT in diurnal occurrence pattern. The Pi pulsations show a midnight maximum in the diurnal pattern. As to the seasonal variation of activity level, the Pc3 and Pc5 pulsations do not show distinct difference between seasons, while Pc4 tends to have a summer enhancement. These features of pulsations observed at this station, which are relevant to this sub-equatorial zone, have been compared to those reported for high, middle and equatorial latitudes