Chaotic Properties and Prediction of Ionospheric TotalElectron Content Based on Cosine and Cluster Analysis

Objective The paper analyzes the chaotic properties of ionospheric total electron content based on the600TEC data from 101～150din 2008over 120°E and 45°N.Calculation results show that the TECtime series is chaotic when correlation dimension is 2.263 2,embedding is 5and largest Lyapunov ex-ponent is 0.083 3.A new method to choose the more similar phase points is advanced based on cosineand cluster analysis while the weighted one-rank local-region forecasting method is used sucessfuly toforecast the time series of TEC.The search results show that the paper’s method can hunt more simi-lar phase points than the euclidean distance and cosine in 5dimensional space.Forecasting resultsshow that the STD(0.618TECU)and RMS(0.623TECU)based on cosine and cluster analysis areless than the other two methods.Therefore,the method can choose by rule and line similar phasepoints and improve forecasting precision.