COMPARISON OF THE ELECTRON DENSITY PROFILES MEASURED WITH THE INCOHERENT SCATTER RADAR, DIGISONDE DPS-4 AND CHIRP-IONOSONDE

The paper is devoted to the comparison of the electron density obtained by the incoherent scatter radar, Digisonde and chirp-ionosonde. The main discrepancies can be explained by influence of ionospheric irregularities of different scales. During the morning hours the strong electron density gradients result that the ionosondes give the overestimated values in comparison with the incoherent scatter radar. The electron density disturbances obtained by the different instruments may have a correlated and uncorrelated nature. Uncorrelated disturbances are associated with intensive ionospheric irregularities of scales less or equal to 100 km. Correlated disturbances are due to ionospheric irregularities of scales considerably greater then 100 km