Fig. 2
From: Statistical analysis of short-wave fadeout for extreme space weather event estimation
![Fig. 2](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs40623-020-01278-z/MediaObjects/40623_2020_1278_Fig2_HTML.png)
a Seasonal variation in monthly averaged fmin as a function of month, b contour map of monthly averaged fmin values in MHz as a function of month and year, c averaged fmin as a function of LT (= UT + 9 h), and d contour map of fmin values in MHz as a function of LT and year. Vertical lines in a, c show the standard deviation, ± 1σ, and line colors distinguish the solar minima and two groups of solar maxima, as labeled in a