Forecasting the dynamic and electrodynamic response to the January 2009 sudden stratospheric warming

In a companion paper, it has been demonstrated that the neutral atmosphere response to the 2009 warming can be simulated with high fidelity and can be forecast several days ahead. The 2009 warming was a major event with the polar stratospheric temperature increasing by 70 K. The neutral dynamics from the whole atmosphere model (WAM) was used to drive the response of the electrodynamics.

The WAM simulation predicted a substantial increase in the amplitude of the 8-hour terdiurnal tide in the lower thermosphere dynamo region in response to the warming, at the expense of the more typical semidiurnal tides. The increase in the terdiurnal mode had a significant impact on the diurnal variation of the electrodynamics at low latitude. The changes in the winds in the dayside ionospheric E region increased the eastward electric field early in the morning, and drove a westward electric field in the afternoon.