ИСТИНА

The methods are suggested for constructing the ionospheric perturbation indices (IPIs) from the empirical electron density distributions retrieved by the ionospheric radio tomography (RT). The indices take into account the specificity of the low- and high-orbiting (LO and HO) RT data, their spatio-temporal resolution and coverage. We consider and analyze various schemes of IPIs construction, calculate the correlation between the IPIs and geomagnetic Kp index, identify the indices that are most sensitive to the geomagnetic activity factor.