Assessment of the solar-cycle dependence of f0F2 1157

Abstract

Comparisons between observed hourly monthly-median values of f0F2 at Slough and Rome, and calculated f0F2 values using as an index of solar activity R12 or T12, demonstrate that there is practically no difference in the results when a solar (e.g., R12) or ionospheric index (e.g., T12) is used. The choice of the index should be based on other criteria. It is also shown that there is a slight degree of favourability for a quadratic law between f0F2 and each index of solar activity. Therefore, in mapping F-layer characteristics a second-degree relation should be adopted independently of rising or falling solar-cycle. Saturation and hysteresis effects could be then minimised.