Fig. 1From: First simulations of day-to-day variability of mid-latitude sporadic E layer structuresTemporal variations of (a) simulated \(\hbox {Ca}^+\) density and (b) zonal (c) meridional and (d) vertical component of neutral winds used as an input. Positive values in Fig. 1b–d represent eastward, southward and upward, respectively. “Layer 1” occurs at daytime and “Layer 2” occurs at nighttimeBack to article page