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Correlations Between the Thermosphere's Semiannual Density Variations and Infrared Emissions Measured With the SABER
D R Weimer1,2, M G Mlynczak3, J T Emmert4
1Center for Space Science and Engineering Research Virginia Tech Blacksburg VA USA.
Journal of Geophysical Research. Space Physics
|April 23, 2019
Summary
This study analyzes thermospheric neutral density variations using satellite drag data and compares them with infrared emissions. Optical emissions show promise for monitoring and predicting semiannual density changes.
Area of Science:
- Earth and Space Science
- Atmospheric Science
- Aeronomy
Background:
- Thermospheric neutral density exhibits annual and semiannual variations.
- Understanding these variations is crucial for satellite operations and atmospheric modeling.
- Infrared emissions from CO2 and NO are potential indicators of thermospheric conditions.
Purpose of the Study:
- To measure and compare thermospheric neutral density variations with infrared emissions.
- To assess the utility of optical emissions as a tool for monitoring thermospheric density.
- To investigate the amplitude and timing of seasonal density oscillations.
Main Methods:
- Utilized atmospheric drag data from multiple satellites (CHAMP, GRACE-A, GOCE, Swarm).
- Employed data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument.
- Calibrated density data using a global average density database and compared with the NRLMSISE-00 model.
Main Results:
- Significant variations in amplitude and timing were found for seasonal density oscillations.
- Filtered carbon dioxide emissions showed good correlation with measured density oscillations.
- A simple Fourier series also effectively predicted density oscillations, contrary to initial expectations.
Conclusions:
- Optical emissions, particularly from carbon dioxide, can serve as a practical tool for monitoring thermospheric density variations.
- Future research should leverage these optical measurements for improved understanding and prediction of semiannual variations.
- The study highlights the complex interplay between neutral density and infrared emissions in the thermosphere.
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