Fig. 3From: Sporadic E layer characteristics at equatorial latitudes as observed by GNSS radio occultation measurementsPlot a shows an ionogram recorded by the São Luís station in the afternoon of 1 May 2006. The ionogram shows an Esq signature. Plot b illustrates a co-located (2.6\(^\circ\)S, 42.5\(^\circ\)W) normalized SNR profile recorded by the CHAMP satellite at 15:06 UT. The Esq layer is not visible in the SNR profileBack to article page