Thermospheric Density Enhancements from Unexpected Energy Deposition During Bz North and Strong By...
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Transcript of Thermospheric Density Enhancements from Unexpected Energy Deposition During Bz North and Strong By...
Thermospheric Density Enhancements from
Unexpected Energy Deposition During Bz North and Strong By Conditions
Geoff Crowley, ASTRA
Delores Knipp, NCAR
Kelly Ann Drake , USAF Academy
Jiuhou Lei, CU
Thanks
TIMEGCM /AMIE – Art Richmond/NCARData Providers – SuperDARN, DMSP, Ground Magnetometers
CHAMP Neutral Density at ~400 km
*10-12Kg/m3
*10-12Kg/m3
4
4 8 12 16 20 06 10 14 18
8 12 16 206 10 14 18 0DAYSIDE
NIGHTSIDE
Aug 24, 2005 (day 236)
CHAMP Neutral Density at ~400 km
*10-12Kg/m3
*10-12Kg/m3
4
4 8 12 16 20 06 10 14 18
8 12 16 206 10 14 18 0DAYSIDE
NIGHTSIDE
Aug 24, 2005 (day 236)
Aug 24, 2005 (day 236)“lobes” appear at 6-8 UT in both hemispheres
6UTShock, By turns strongly +ve
TIMEGCMCHAMP
F15 07:51UTAMIE 07:50UTPOTENTIAL
JOULE HTGFAC
• AMIE (magnetometers, DMSP, SuperDARN)• 5 min cadence
TIMEGCM 08:00 UT
Neutral Density(RHO)
Vert. Wind (W)
TIMEGCM forced with AMIE high latitude fields
• AMIE (magnetometers, DMSP, SuperDARN)• 5 min cadence
Outer Lat = 2.5°
CHAMP Neutral Density at ~400 km
*10-12Kg/m3
*10-12Kg/m3
4
4 8 12 16 20 06 10 14 18
8 12 16 206 10 14 18 0
Southern Hem peak
F15 16:20 UTAMIE 16:20 UTPOTENTIAL
JOULE HTGFAC
Note: Effect evident in AMIE as early as 15:45, but not seen by DMSP
CONCLUSIONS Poynting Flux Enhancements
• CHAMP sees unexpected density enhancements for BZ-north and strong BY events
• DMSP sees strong Poynting flux enhancements at very high latitudes (Delores)
• AMIE provides a global framework to confirm PF events
Poynting Flux Enhancements
• TIMEGCM densities often mimic CHAMP observations
• TIMEGCM reveals PF-events produce large density enhancements
• Density enhancements tend to be isolated at high latitudes
Density decrease
• Long-lived event from 16-24 UT produces density ‘hole’
• Density decrease measured by CHAMP
• Hypothesis: depletions due to dynamical effect (Crowley - cells)
Gravity Waves
• Large-scale gravity waves evident in TIMEGCM correspond to other
CHAMP density structures (not discussed in detail)