A method for automatic scaling of F1 critical frequencies from ionograms

This work describes a method that has been developed to automatically assess
whether the F1 layer is present or not on an ionogram trace, and, if present, to scale the
F1 critical frequency foF1. The ionograms in which the information related to the F1 trace
is insufficient are identified and considered separately. In order to test the performance of
this method and the conditions in relation to which it could be improved, a data set of
ionograms recorded from September 2005 to June 2006 by the AIS-INGV ionosonde
installed at Rome was used. The values obtained automatically by Autoscala, with the
addition of this new F1 layer routine, were compared with those obtained by the standard
manual method.

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