Mapping of ionospheric irregularity and scintillation spectral indices for Northern Europe

In situ satellite observations have previously been employed to map the global morphology of electron density irregularity parameters which define scintillation. In particular the power exponent of the inverse spatial spectrum of the irregularities p_i can be determined which will yield the slope p of the psd of the resultant scintillation from p=p_i -1. This also means that the inverse spatial spectrum of the irregularities can be determined from the measured slope of the resultant phase scintillation (or amplitude scintillation above the Fresnel frequency) by measuring the slope of its PSD (on log log axes). The in situ measurement has the advantage of good temporal and spatial coverage but the disadvantage that a satellite in orbit at ionosphere altitudes is required. In this paper we present a method of determining the value of p and hence also pi from just scintillation indices (S4 and σ_φ) thus obviating the need for in-situ measurements or the necessity of deriving the fading frequency spectrum from FFTs of high (e.g 50 Hz) rate data. With the addition of an extensive data set from a number of ground-based scintillation monitoring stations this provides a way of easily investigating the variation of these spectral and irregularity parameters with location, time of day, season, Kp, solar activity etc.