DETECTION OF AN EQUATORIAL SPREAD-F BUBBLE BY GROUND-BASED PHOTOMETERS AND THE SAN-MARCO-5 SATELLITE

In the Fall of 1988, San Marco 5, instrumented with ion density and el ectric field experiments, made passes through the equatorial F-region in the Brazilian sector, where scanning photometers have been operated at Cachoeira Paulista, Brazil, for many years. We have cross-checked these large data sets and report here on one night of active spread-F with good data from both San Marco 5 and Cachoeira Paulista. As expect ed, a correlation is observed between airglow bubbles and ion density depletions encountered by San Marco 5. Additional airglow bubbles can be linked to enhanced AC electric field fluctuations, similar to those previously suspected to characterize satellite passes through pinched off spread-F bubbles. These data complement existing airglow-satellit e correlations made in other longitude sectors and provide information relevant to the interpretation of satellite and airglow data. (C) 199 7 Elsevier Science Ltd.