Multistation digisonde observations of equatorial spread F in South America
- 1University of Massachusetts Lowell, 600 Suffolk St., Lowell MA 01854, USA
- 2Instituto Nacional de Pesquisas Espaciais, Ave dos Astronautas 1758 C.P. 515 12202-970 Sao Jose dos Campos, SP, Brazil
- 3Air Force Research Laboratory, 29 Randolph Road, Hanscom AFB, MA 01731, USA
- 4Jicamarca Radio Observatory, Instituto Geofísico del Perú, Apartado 13-0207, Lima 13, Peru
- 5University of Tucuman, Av. Independencia 1800, (4000) San Miguel de Tucuman, Argentina
Abstract. Directional ionogram and F-region drift observations were conducted at seven digisonde stations in South America during the COPEX campaign from October to December 2002. Five stations in Brazil, one in Argentina, and one in Peru, monitored the ionosphere across the continent to study the onset and development of F-region density depletions that cause equatorial spread F (ESF). New ionosonde techniques quantitatively describe the prereversal uplifting of the F layer at the magnetic equator and the eastward motion of the depletions over the stations. Three of the Brazilian stations were located along a field line with a 350-km apex over the equator to investigate the relation of the occurrence of ESF and the presence of sporadic E-layers at the two E-region intersections of the field line. No simple correlation was found.