An examination of the geomagnetic field variations at equatorial stations in South America has shown that the daily range of the northward field, H, is about 30% larger in Peru than in Brazil. The midday H field vector in Brazil shows a large westward tilt, corresponding to large westward declination at the station. A significant meridional trans-equatorial current system is suggested for the observed anomaly. The longitudinal variation in the equatorial electrojet current strength is suggested to be due to the corresponding variation in the ionospheric electric field rather than to the electrical conductivity.
展开▼
