A comparison of ionospheric scintillation proxy indices derived from low rate IGS data with the amplitude scintillation index, S4, in a low latitude region over Africa

Our results show that the weaknesses and strengths of the amplitude scintillation proxies are as follows: ROTI, even though derived from GNSS phase information, corresponds well with the trend of the amplitude index S4 during the generation, evolution and decay phases of signal amplitude. The scintillation proxy derived from the L1 Signal to Noise ratio (S/N) observable (S1) is shown to have a useful correspondence with S4 index.