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Variation in Thermospheric Neutral Density

Stan Solomon and Liying QianHigh Altitude Observatory

National Center for Atmospheric Research

CISM All-Hands Meeting • Boulder, Colorado • 15 September 2008

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Time Scales for Forcing of the Terrestrial Upper Atmosphere

101 102 103 104 105 106 107 108 109 1010 1011 1012 1013 1014 1015 1016 1017

Seconds

Flares

SolarRotation

EarthRotation

SolarCycle

Seasonal

Orbital

Anthropogenic

Geological

Biogenic

Solar Evolution

Solar Cycle Variation??

Geomagnetic

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Start with the Flares — Are They Really Important?

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Flare Spectrum Inferred using Rodgers & Bailey Method

Flare spectrum on 10/28/03 at 11:12 UT obtained using the R&B analysis method

The method of Rodgers and Bailey (R&B) [Rodgers et al., JGR, 2005] obtainsa differential emission measure that best fits signals observed by the multiplebandpasses of XPS diodes on TIMED/SEE or SORCE, and uses the Warrenet al. [1998, 2001] model to produce a flare spectrum.

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SEE Flare Spectra Combined with R&B Method in the XUV

Combined TIMED/SEE and SORCE spectra for 10/28/03using the R&B method.

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Energy Deposition in the Upper Atmosphere — Pre-Flare

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Energy Deposition in the Upper Atmosphere — During Flare

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Estimate of the Time Dependence

EUV Data from TIMED/SEE (linear interpolation)

XUV Data from SORCE/XPS (R&B method scaled w. GOES)

X-ray Data from GOES X-ray monitor

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NCAR TIE-GCM Simulation for the 10/28/03 Flare

E-region electron density (~115 km) F-region electron density (~350 km)

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NCAR TIE-GCM Simulation for the 10/28/03 Flare

Neutral temperature at ~350 km Height of the +2 pressure surface

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Comparison of Observations to Model for 10/28/03 Flare

Neutral DensityMeasurementsfromaccelerometerson CHAMPand GRACEsatellites

TIE-GCMSimulationsat samealtitude andlocal time

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Total Electron Content Measurement and Model

Total Electron Content increases on10/28/03 from GPS observations

[Tsurutani et al., 2004].

Total Electron Content increases simulatedusing the NCAR TIE-GCM

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TIE-GCM Simulation of the 10/28/03 Flare and Storm

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Thermospheric Variability on (Slightly) Longer Time Scales

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Taifun-1 Radar Calibration Satellites

1983-11-11COSMOS 150814483

1981-04-09COSMOS 126312388

1981-01-16COSMOS 123812138

1976-03-12COSMOS 80708744

1974-06-18COSMOS 66007337

Launch DateNameNORAD Catalog Number

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COSMOS 1508 gets its 15 Minutes of Fame

“On a September 15EVA Solovyov andAvdeyev retrieved solarcell and materialssamples and moved theKurs rendezvousantenna on Kristall so itcould be used by SoyuzTM-16. Thecosmonauts releasedthe 16.5-kg MAK-2satellite from the Mirbase block sexperiment airlock onNovember 20. Itspurpose was to studyEarth s ionosphere. Thederelict 550-kg Cosmos1508 satellite, launchedby the Soviet Union in1983, passed within300 meters of Mir onNovember 8.”

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Orbital Characteristics of Satellite Drag Measurements

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Model-Data Comparison for 2003

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Model-Data Comparison for 2003

07337

08744

12138

12388

14483

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Average Model-to-Data Ratio for 2003

0.140.20Std. Dev.

0.991.03Mean

TIE-GCMMSIS-00

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Model & Measurement of Thermosphere Solar Cycle Variation

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