High-Resolution 3-D Simulations of the Thermospheric Response to Magnetic Storms, Substorm Surges and the Diffuse Aurora

Investigator(s):

Helen Parish (PI) ; Lawrence Lyons (Co-PI)

Sponsor:

University of California-Los Angeles, CA 90024 3107940102

Start Date/Expiration Date

2003-03-15 to 2006-02-28 (amended 2005-03-04)

Awarded Amount to Date:

$264,519

Abstract: The investigators will study the response of the E region neutral thermosphere to enhanced auroral forcing. In particular, the aim is to explain and understand phenomena observed within the dawn and dusk recovery phase diffuse aurora, and the thermospheric response to expansion phase surges and new phenomena observed during large magnetic storms. These topics involve areas that are of importance to the space physics and aeronomy community where knowledge is limited. Previous work entailed the simulation of thermospheric response to the dawn sector diffuse aurora using a 3-dimensional (3-D), high resolution, non-hydrostatic, composition-dependent model. The model was able to reproduce the very strong shears in the region of the dawn sector diffuse aurora and unstable regions below the shears, within the same altitude range as those found in the ARIA (Atmospheric Response in Aurora) rocket measurements. The results of the previous research project suggested that propagating tidal modes play an important role in producing the observed structure, in addition to geomagnetic forcing. In this study, the investigators will model the effects of enhanced auroral forcing on the region of the dawn and dusk sector diffuse aurora, for a series of rocket campaigns, using the 3-D high resolution model. The model will be used to determine the mechanisms responsible for producing the observed structures in both the dawn and dusk diffuse aurora, how and why the dusk response differs from the dawn response, the effects of changes in the interplanetary magnetic field (IMF) on wind magnitudes and structures, and the sensitivity to changes in conditions of solar and geomagnetic activity and tidal forcing. The investigators will also determine the dynamical, thermal, and compositional response of the E region thermosphere to the intense precipitation associated with expansion phase auroral surges, as well as the thermospheric response to recently observed large magnetic storms which show characteristics inconsistent with the effects of substorms. The results of the research will be made available to the scientific community, and will include systematic details of the response of the winds, composition and temperature in the E region thermosphere to the enhanced auroral forcing associated with magnetic storms and substorms for varying solar and geomagnetic activity, IMF orientation, and tidal forcing. The model will also be made available for use in collaborative research projects and for research and teaching studies involving graduate and undergraduate students.

NSF Org:

ATM - Division of Atmospheric Sciences

Award Number:

0242292

Award Instrument:

Continuing grant

Program Manager:

Robert B. Kerr
ATM Division of Atmospheric Sciences
GEO Directorate for Geosciences

NSF Program(s):

AERONOMY

Field Application(s):

Space

Program Reference Code(s):

UNASSIGNED, 0000

Program Element Code(s):

1521