Figure 3From: Lidar returns from the upper atmosphere of Kamchatka for 2008 to 2014 observationsCritical frequency of the ionospheric F2 layer and lidar signals with the indicated degree of filtration. (a) Critical frequency of the ionospheric F2 layer (foF2) and (b) lidar signals with the indicated degree of filtration summed for altitudes of 200 to 300 km.Back to article page