| Popis: |
The results of analyses of earth current measurements at two stations in Ghana—Legon (5°38′N, 0°11′W) and Tamale (9°25′N, 0°53′W)—are discussed and it is suggested that in the equatorial region, the electrojet causes an enhancement of the solar daily variation of the earth currents by a factor of 6 or less. To account for the seasonal change in the S q variation, it is suggested that there may he a seasonal shift in the mean position of the S q current system and of the electrojet. The annual mean S D hodograph has been constructed and shows a marked deviation from its average behaviour at approximately 1800 hours. An estimate of the magnitude of the lunar variation of the earth currents at Legon has also been obtained from one year's data. It is approximately 12 per cent of the solar daily variation. |
