Some observations of ionospheric absorption at geomagnetic conjugate stations in the auroral zone

Evidence is presented to show that strong ionospheric absorption often occurs simultaneously at the nearly magnetically conjugate stations of Farewell and Campbell Island. The absorption can be attributed to polar-cap and aurorally associated absorption events. During polar-cap absorption events, the boundary of the absorption regions appear to occur at the same effective magnetic latitude in the northern and southern hemispheres. Absorption associated with the aurora generally occurs simultaneously at Farewell and Campbell Island, but approximately 3° north and south absorption often occurs in an independent pattern.