astrid maute, art richmond, ben foster
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Astrid Maute, Art Richmond, Ben Foster. The NCAR Themosphere-Ionosphere-Electrodynamics General Circulation Model: Problems in Developing a Realtistic Model. 22 May 2007. Outline. Description of the system Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) - PowerPoint PPT PresentationTRANSCRIPT
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High Altitude Observatory (HAO) – National Center for Atmospheric Research (NCAR)
The National Center for Atmospheric Research is operated by the University Corporation for Atmospheric Researchunder sponsorship of the National Science Foundation. An Equal Opportunity/Affirmative Action Employer. 18 March 200322 May 2007
Astrid Maute, Art Richmond, Ben Foster
The NCAR Themosphere-Ionosphere-Electrodynamics General Circulation Model: Problems in Developing a Realtistic Model
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Outline
SAMSI meeting 22 May 2007
•Description of the system
•Thermosphere-Ionosphere-Electrodynamics
General Circulation Model (TIE-GCM)
•Our Experiment
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Electron and Neutral Density
SAMSI meeting 22 May 2007
Day-night difference
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Spatial Variation: Equator
SAMSI meeting 22 May 2007
2001-09-10,7:30-8:03, long=67., F10.7=245
b0
B
[nT
]
100
-10
-20
-30-40
observations
mag. latitude [deg]
p.approxfor.correct
-40 -20 0 20 40
H at 12 SLT
upward ExB drift at magn. equator
CHAMP satellite at 12 LTMagnetic perturbation
on the ground
[Luehr et al. 2003]
H northwardD eastward
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Spatial Variation: High Latitude
SAMSI meeting 22 May 2007
field-aligned current
coupling to the magnetosphere
closed field lines
open field lines
[Richmond et al. 2000]
night
+/- electric potential
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Geomagnetic grid
SAMSI meeting 22 May 2007
geomagnetic equator
[Richmond 1995]
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Geomagnetic / Geographic Grid
SAMSI meeting 22 May 2007
equivalent current
geomagnetic equator
17 UT 13 UT
magnetic perturbationat 12 LT
[Doumbia et al. 2007]
• D eastward
geog. longitude
• Variation with longitude
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Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIE-GCM)
SAMSI meeting 22 May 2007
•Self-consistently calculates neutral and ion densities, composition, velocities, temperatures, along with electric fields and currents, between 97 and 500 km, assuming vertical hydrostatic equilibrium. •Basic resolution is 5x5 degrees horizontally, ½ scale height (3-30 km) vertically, dimensioned 73(longitude) x 36 (latitude) x 29 (height)•1-day simulation uses ~ 3 minutes on bluevista, with 3-minute time step.
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TIE-GCM: Interacting Physics
SAMSI meeting 22 May 2007
Global Electrodynamo
Thermosphere Ionosphere
tides at the lower boundary
high latitude electric fields
solar radiation, auroral precipitation, ion flux at
upper boundary
neutral windsion drag
conductivities
ion composition
neutral composition
neutral temperature & wind
ion drag
input parameters
internal parameters + many others
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TIE-GCM: How the models is used
SAMSI meeting 22 May 2007
•Studies of geomagnetic storms
•Yearlong runs for seasonal
studies
•Model runs with daily varying
input (e.g. using NCEP data)
•Generic input parameters to
study certain effects
[Flyer of TIME-GCM]
Joule heating [mW/m2] for 18. Oct. 1995 storm
Difference in temperature after doubling global CO2 concentration
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TIE-GCM: “tuning” the model
SAMSI meeting 22 May 2007
•Lots of parameters which would need tuning
or could be improved
•Simplification of parameters, e.g. ignore
latitudinal variation, seasonal dependence
•Model response is not necessarily linear, i.e.
cannot “tune” for one parameter after another
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Observations
SAMSI meeting 22 May 2007
•Local with varying local
time and location
•Dependence on season,
solar cycle and activity
•Datatypes: neutral wind,
electron density, magnetic
field, drift velocity, neutral
density
Local time
[Scherliess et al. 1999]
Jicamarca 1968-92 Kp<3
Sa > 150
100 < Sa < 150
Sa < 100
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Empirical models
SAMSI meeting 22 May 2007
•International Reference Ionosphere (IRI) model
•Mass-Spectrometer-Incoherent-Scatter (MSIS) model
Global, can define specific conditions
Log10 Ne [1/cm3] at 12 LT at equator
IRI 2001 TIE-GCM
•Electron density (Ne) in TIE-GCM 40 to 60% too low depending on altitude•Increase of B in our experiment
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MSIS and IRI
SAMSI meeting 22 May 2007
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Our First Plan
SAMSI meeting 22 May 2007
Initial plan was to vary 7 parameters:
•Tidal input (2,2) and (2,4) mode with amplitude and
phase 4 parameters
•Eddy diffusion
•Burnside factor
•Nighttime electron density
•Use data from IRI (electron density height and
magnitude of peak density), B, drift velocities, MSIS
(composition, temperature)
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Our Experiment
SAMSI meeting 22 May 2007
Reduce to 3 parameters:
•Tidal input (2,2) migrating mode with amplitude and
phase
Range for amplitude [0,360] m and phase [0,12] hrs
•Nighttime electron density (internal parameter)
Range for log10 Ne [3,4] 1/cm3
Use data from B, drift velocities at different stations
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Why these parameters?
SAMSI meeting 22 May 2007
LT
LT
[Fesen et al. 2000]
prereversal enhancement in the early
evening
no influence on daytime
tides influence the daytime drift,
as well as time and magnitude of
early evening peak
nighttime changes
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Influence of tidal modes on B
SAMSI meeting 22 May 2007
H H D D
observationbackground
(2,2)(2,3)(2,4)(2,5)(2,6)
tidal modes
phase shift: 0 & 3 hrs
Fuquene (geog. lat./long. = 5.3o/ -74.o)
•determine tidal amplitude and phase•least square fitting to magnetic perturbations around the world
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Datatypes
SAMSI meeting 22 May 2007
Conditions: solar minimum, quite time, equinox
Use data from B, drift velocities at different stations
JRO
ARC MU
STSMH
drift velocities
magnetic perturbation
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Example:B
HAO colloquium 8 September 2004
SJG
FRD
FUQ
PIL
HUA
TRW
AIA
mag
n. la
titud
e
60
40
20
0
-20
-40
-600 6 12 18 24
MLT
HAmerican sector
PET
MGD
KAK
KORGUA
PMG
BRS
TOO
H
mag
n. la
titud
e
60
40
20
0
-20
-40
-600 6 12 18 24
MLT
100 = 30 nT
TIEGCM
Observations
Asian/Australian sector
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30 TIE-GCM runs
SAMSI meeting 22 May 2007
• Amplitude of (2,2)
migrating tide: [0,360] m
• Phase of (2,2) migrating
tide: [0,12] hrs
• Nighttime electron
density: log10 Ne [3,4]
1/cm3
Error on our code: electrons and ions not in balance
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30 TIE-GCM runs
SAMSI meeting 22 May 2007
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SAMSI meeting 22 May 2007
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SAMSI meeting 22 May 2007
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SAMSI meeting 22 May 2007
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SAMSI meeting 22 May 2007
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SAMSI meeting 22 May 2007