Day-to-day variability of the equatorial electrojet current in the South American sector

A comparison of the geomagnetic H field data at Ancon, Peru and Buriticupa, Brazil for the period December 1990 and January 1991 revealed the presence of a significant correlation in day-to-day variability in the solar daily variation of H at the two stations, which are separated by about 2000 km. It is suggested that the day-to-day variability in the time as well as in the magnitude of the daily peak of the H field at an equatorial electrojet station is due to the superimposition of a semi-diurnal wave of the electric field over the normal mean daily variation.