Numerical modelling of the Weddell sea anomaly in behaviour of the ionospheric F2-region

The morphology and mechanism of the Weddell Sea Anomaly (WSA) forming has been investigated by using the global numerical model of the Upper Atmosphere Model and empirical model of the ionosphere IRI-2001. It has been shown that both models reproduce WSA in the summer southern hemisphere in longitudinal sector 255-315E. It has been found that the analogous WSA longitudinal variation of the electron density takes place in the summer northern hemisphere in longitudinal sector 75-135E. It has been shown that both phenomena are caused by the non-coincidence of the geomagnetic and geodetic axes which produces the difference in vertical velocities of the ion transfer by the thermospheric wind action in the western and eastern longitudinal sectors.