Time/altitude electron density variability above Ebro, Spain

The time series of electron density profiles N(h) obtained at midlatitude station Ebro (40.5°N, 0.5°E) since 1995 up to now have been evaluated in order to obtain the typical time/altitude electron density variability. The standard deviation σ(h) of the individual profiles from Monthly Averaged Representative Profile (MARP) is used for such purpose. The percentage of σ(h) vs. MARP shows a distinct daily, seasonal and altitude pattern of variability. As expected, the larger variability occurs during night-time, there being however much better expressed at the base of the F region. Typical values of percentage of variability at altitudes of the electron density maximum are 10-20%, whereas they can be as large as 50% during night-time at the base of the F region. The systematic daily, seasonal and long-term behaviors of σ(h) are discussed in terms of potential modeling purposes. The potential physical causes driving systematic behavior of σ(h) are discussed also.