Impact of the vertical dynamics on the thermosphere at low and middle latitudes: GITM simulations
Abstract
In this study, the influences of the electric fields at low and middle latitudes on the ionosphere and thermosphere are investigated by using the nonhydrostatic Global Ionosphere and Thermosphere Model (GITM). The equatorial ionization anomaly and the equatorial thermosphere anomaly (ETA) are well reproduced in the simulation when the electric fields are included. The term analysis of the continuity equation of the neutral mass density shows that the daytime upward vertical wind near the geomagnetic equator tends to increase the local neutral mass density at 400 km altitude, while the divergence in the meridional wind associated with the meridional ion‐drag force tends to transport the neutral mass density away from the geomagnetic equator which might contribute to the formation of the ETA trough. The vertical dynamics is modulated by the vertical forces including ion‐drag force and pressure gradient force acting on the neutrals, and the changing vertical dynamics can also feedback to vertical ion‐drag and pressure gradient forces, particularly near the geomagnetic equator. The daytime vertical ion‐drag force near the geomagnetic equator is generally upward, while the daytime vertical pressure gradient force near the geomagnetic equator is reduced at most times after adding in the electric fields at low and middle latitudes. Meanwhile, the sudden introduction of the electric fields at low and middle latitudes induces an acoustic wave.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 01, 2017
- Source ID
- 10.1002/2017ja023939
Entities
People
- Astrid Maute
- Cheng Sheng
- Cissi Lin
- Qingyu Zhu
- Yue Deng
Organizations
- Air Force Office of Scientific Research
- Harold and Muriel Berkman Charitable Foundation
- High Altitude Observatory
- National Aeronautics and Space Administration
- National Science Foundation
- University of Texas at Arlington