摘要：We explore the concept of using an all-sky imager (ASI) in one hemisphere to provide nowcasting of ionospheric perturbations in the opposite hemisphere. The specific example deals with low-latitude plasma instabilities known as equatorial spread F (ESF) that largely depend on geomagnetic field controlled electrodynamics. ASI observations of 630.0 nm airglow from ~300 km exhibit regions of low emission (“airglow depletions”) that correlate highly with ESF patterns of radio wave disruptions, for example, from GPS satellites. For both oceanographic and geopolitical reasons, there are vast regions of the globe that cannot be used for ground-based nowcasting of local ESF effects. For such area-denied locations, it is possible to use observations of airglow depletions from the opposite hemisphere to specify both local and conjugate location environmental impacts. We use 15 months of ASI observations from the El Leoncito Observatory (Argentina) to predict simultaneous conditions at its trans-equatorial geomagnetic conjugate point in Villa de Leyva (Colombia)—validated by independent ASI observations at that location. We find the success rate of conjugate point nowcasting to be greater than 95% for large-scale ESF occurrence patterns. For a different pair of stations at higher magnetic latitudes, 3 years of observations from the Arecibo Observatory (Puerto Rico) were used to make ESF nowcasting at its conjugate point in Mercedes (Argentina) with a similar high success rate.
