Diagnosis of Quasi-Wave Disturbancesin the Topside Ionosphere by Modified SSA Method
This paper presents a modified SSA (Singular Spectrum Analysis) method, specially designed for the analysis of weak quasi-wave disturbances of the plasma density in the topside ionosphere. Its special feature is the transformation of the original series of latitudinal distribution of the electron density at a fixed height in the new array. This is achieved by removing trend from the original series and subsequent double differentiation of residue. This procedure solves two tasks. The first decision eliminates the constant and linear component in the residue of trend. The second decision provides more contrast manifestation of the harmonic component in a new series. Method was tested by model calculations and real observational data. It showed high resolution.