MODELLING M(3000)F2 AT AN AFRICAN EQUATORIAL LOCATION FOR BETTER
IRI-MODEL PREDICTION
Abstract
The F2-layer propagation factor M(3000)F2 is important to
ionospheric studies owning to its use in HF radio
communication/ionospheric modelling. This study focused on reducing the
shortcomings in the use of M(3000)F2 IRI-model for obtaining
hmF2, especially in the African equatorial region, by obtaining
an empirical ‘constructed model’ (M(3000)F2CM
) using the Korhogo (geomag. lat. 1.26°S, long.
67.38°E, dip.-0.670S) data
(M(3000)F2KOR). The data spans 8 years
(1993-2000) under magnetically quiet conditions (Ap<
20nT). The Regression method technique was used in obtaining the
M(3000)F2CM. The
M(3000)F2KOR results revealed that low solar
activity (LSA) years have predominantly higher magnitudes than high
solar activities (HSA) for all seasons, revealing solar activity
dependence. The regression coefficient (R2) for
the M(3000)F2KOR versus F10.7 relationship
was stronger during the solstices. The associated diurnal equations
obtained for all seasons from the regression plot of the
M(3000)F2KOR-F10.7 relationship were used
to obtained the constructed model equation given by , which allows the
prediction of diurnal, seasonal and solar cycle variation of the
M(3000)F2 parameter. M(3000)F2CM
predicted well when tested at different solar
activities. Generally, M(3000)F2CM
performed reasonably well in comparison with the IRI
model (M(3000)F2IRI) when validated with
Ouagadougou (lat. 0.59°S, long. 71.46°E) observed data -
M(3000)F2OUA. The %deviation of
M(3000)F2CM versus
M(3000)F2OUA during HSA and LSA ranges from
-10.8- 5.3/-7.6 - 15.8 for solstices/equinoxes; whereas %deviation of
M(3000)F2IRI versus
M(3000)F2OUA spans -15.5 - 9.2 and -9.7 - 17.7 in
similar order of seasons. These results suggest that the new model has a
measure of potential for its use in the equatorial region.