Comparação do Modelo IRI-79 para a Baixa Ionosfera com Dados de Refletividade de LF/VLF

Abstract

Reflectivity data of the lower ionosphere in the region of the South Atlantic Geomagnetic Anomaly were collected by an oblique ionosonde of Low/Very Low Frequency, between August 1980 and July 1981. Reflection heights and coefficients of the lower ionosphere were obtained by processing the data according to the methods described by Lewis et al., 1973. Average reflection heights and coefficients were calculated for each month of the period. Reflection heights and coefficients corresponding to the IRI- 79 model, for each month of the period, were calculated by applying full wave calculations to the model. A comparison between the reflection heights and coefficients obtained through the model shows that the IRI-79 model can well represent the lower ionosphere in the region of the South Atlantic Geomagnetic Anomaly, from middle local autumn to middle local winter (from May to July) but it is not so good to represent the lower ionosphere for the period between August to April.