HAO Colloquium Series Presents Wenbin Wang, HAO

The dynamical response of the coupled thermosphere and ionosphere to geomagnetic forcing

The Earth’s thermosphere and ionosphere is a weakly ionized layer of the atmosphere that is hugely influenced by external forcing. This forcing includes solar radiation, geomagnetic activity and lower atmospheric waves. In this talk, I will describe how the forcing drives the thermospheric circulation.  The talk will primarily focus on the dynamical response of the thermosphere and ionosphere to geomagnetic forcing using NCAR’s Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) and the Coupled Magnetosphere Ionosphere Thermosphere (CMIT) model. Unexpectedly, neutral winds have strong vertical shears in the upper thermosphere during geomagnetically active periods and sometimes even during quiet times. The physical causes of these vertical shears will be explored here. Other coupling processes also drive strong changes in neutral circulation. For example, storm-time subauroral polarization streams (SAPS) drive strong thermosphere winds and large ionosphere electron density changes.  These storm-time responses also have large longitudinal variations, which will be discussed in this talk. Finally, the influence of solar activity on the response of the coupled thermosphere and ionosphere to geomagnetic forcing will be illustrated. 

Due to technical difficulties, only the last 15 minutes of the presentation was recorded.

Date and time: 
Thursday, September 11, 2014 - 10:00am to 11:00am
Event document: