CTIPe physics based model during the extreme geomagnetic storm on the 20th November 2003

Kurzfassung

Significant perturbations were produced in the thermosphere-ionosphere-magnetosphere system during the geomagnetic storm of the 20th November of 2003, one of the largest ever recorded. Under these extreme conditions, modelling the ionosphere will be a challenging task due to energy flow uncertainties. This work addresses the ionospheric perturbations over Europe, reproduced by the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) physic based numerical code [1,2] and compared with observations of the Total Electron Content (TEC) derived from Global Navigation Satellite System (GNSS) measurements [3] and ionosonde measurements. Travelling Ionsopheric Disturbances (TIDs) are the signatures of atmospheric surges causing neutral composition changes, and are associated with strong TEC enhancement as the one observed during the 20th November 2003 storm. CTIPe reproduce the strong perturbations in Joule heating and neutral winds over Europe, located at exactly the location of the source region of TIDs. Even the signatures of atmospheric surges with similar characteristics of the observed TIDs are reproduced by CTIPe. Joule heating initiated meridional winds [4] and the associated storm-time neutral circulation seem to be the main driver of the ionospheric perturbations observed over Europe. However, comparisons with GNSS measurements show that the TEC enhancement (Fig.1) and TEC rate over Europe are underestimated by the CTIPe model. Nevertheless, the results provide valuable information on the physics of the processes that operate in the ionosphere/thermosphere during this extreme geomagnetic storm, and they may be improved by using better estimates of the thermosphere/ionosphere forcing during the storm.