SPACE WEATHER EFFECTS IN THE BEHAVIOR OF THE IONOSPHERIC TOTAL ELECTRON CONTENT

The total electron content (TEC) of the ionosphere is an important parameter characterizing the space weather, because its behavior depends on the state of the ionosphere and plasmasphere, so even the magnetosphere. The trend towards replacing the use of TEC instead of the maximum plasma concentration NmF2, the attempts to create an index of disturbance of the ionosphere, allowing to predict the variation of NmF2 based on the global distribution of TEC, force to return to the evaluation of the relations between the TEC and NmF2, delta TEC and delta NmF2, specially for disturbances. Investigation of the behavior of TEC and NmF2 and evaluation of the correlation coefficients were conducted on the example of April 2002, including 2 periods of enhanced Bycomponent of IMF and the period of the classical negative disturbance with min Dst similar to -150 nT, according to North American and European chains of stations of vertical sounding and global maps of TEC. It is shown that: 1) disturbance of TEC and NmF2 may occur during amplification of Bycomponent of the IMF, although they are weaker than disturbances in classical magnetic storm and penetrate less deeply in latitude, 2) the correlation coefficients. (TEC, NmF2) weakly dependent on the type of disturbance, decreasing to values of similar to 0.6 at high latitudes. The correlation coefficients.(delta TEC, delta NmF2) may drop to values of 0.2 divided by -0.4, which indicate an inconsistency of variations in the magnetosphere and ionosphere, 3) use of the TEC and the median equivalent slab thickness of the ionosphere allows to recover a picture of the NmF2 behavior in the absence of data of vertical sounding except in cases of strong disturbances.