AbstractThe global perturbation index, σDGEC, of the total electron density (TEC) is estimated from the global ionospheric maps (GIMs) produced by Jet Propulsion Laboratory (JPL). With the use of the Partial Correlation Analysis method we analyze the correlation between the global TEC perturbation index and several other factors such as the solar radio flux at 10.7 cm (F107) and its perturbation (dF107), the geomagnetic Ap index, as well as seasonal factors. The result reveals that σDGEC is much correlated with F107 and Ap, and also correlated with the products of different factors, such as F107×S, F1072, F107 × A and dF1072. Thus, we choose these factors and their multipliers to create a multiple regression model of σDGEC. The index σDGEC may efficiently represent the characteristics of the global TEC perturbation and strongly correlates with the solar activity and the magnetic disturbance. Thus, it is suggested that the global TEC perturbation index σDGEC can be chosen as a new parameter to describe the ionospheric disturbances, especially the state of the space weather in the ionosphere.