Accession Number:

ADA592729

Title:

Thermospheric Mass Density Specification: Synthesis of Observations and Models

Descriptive Note:

Final rept. 27 Sep 2012-27 Jun 2013

Corporate Author:

COLORADO UNIV AT BOULDER OFFICE OF CONTRACTS AND GRANTS

Personal Author(s):

Report Date:

2013-10-21

Pagination or Media Count:

16.0

Abstract:

The objective of the project was to improve the thermospheric mass density specification by synthesizing a host of global observations of the thermosphere and ionosphere with a general circulation model and by characterizing the density variability associated with various external forcing. We have assimilated the neutral mass density data sampled from the Air Force AF High Accuracy Satellite Drag Model HASDM into the NCAR- Thermosphere-Ionosphere-Electrodynamics General Circulation Model using an ensemble Kalman filter assimilation procedure, and adjusted both neutral temperature and major composition mass mixing ratio globally. Global HASDM data appear to be more effective to reduce errors in the global mass density than in-situ observations obtained along satellite orbits in terms of the global neutral density specification. Among all sources of external forcing, the electromagnetic forcing in high-latitudes resulting from the solar-wind-magnetosphere interactions has the most significant impact on the mass density variability. We showed evidence that solar wind density enhancements and pressure pulses can cause intense low-energy particle precipitation and associated damping of thermospheric density response due to enhanced production of nitric oxide - an active infrared cooling agent. Ground-based indices as used by AF Space Command fail to capture these interactions in forecasting algorithms.

Subject Categories:

  • Atmospheric Physics
  • Numerical Mathematics
  • Computer Programming and Software

Distribution Statement:

APPROVED FOR PUBLIC RELEASE