Comparison of Ionospheric Response to Two Types of Electron Concentration Disturbances

Based on the data of vertical sounding of the ionosphere in Almaty in 2000-2008, the paper deals with the response of the F2-layer to the passage of large-scale traveling ionospheric disturbances (LSTIDs) and the formation of the nighttime enhancements in the electron concentration of the F2-layer. For these two types of perturbations, we compared behavior in the time of the following layer parameters: the height of maximum of the layer (h(m)F), the height of the bottom of the layer (h(bot)F), the half-thickness of the layer (Delta h = h(m)F - h(bot)F), the electron concentration at fixed heights and at the maximum of the layer (NmF), the height profiles of the nighttime enhancement peak-to-peak value of the F2-layer (A), and the height h(Am) corresponding to the maximum enhancement amplitude. The parameters h(m)F, h(bot)F and Delta h demonstrate similar dependences associated with the temporal expansion and upward rise of the ionospheric layer and its lowering, accompanied by layer compression, giving an NmF peak at the moment of maximum compression. The common features of the profiles of two types of disturbances are found: the height h(Am) is always below h(m)F, there is a good correlation between h(Am) and h(m)F, and the difference between h(Am) and h(m)F increases linearly with h(m)F.