LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with...
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Transcript of LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with...
![Page 1: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/1.jpg)
LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere
(Comparisons with JRO ISR Drift Measurements)
Vince Eccles (Modeling)
Space Environment Corporation, Providence, Utah
Erhan Kudeki (JRO ISR)
University of Illinois
Cesar Valladares (LISN)
Boston College
![Page 2: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/2.jpg)
Assimilation of Ionospheric Data for the Low-Latitude Ionosphere
• Ionospheric model-data assimilation methods typically modify electron density specifications to best match TEC observations.– 3D ionospheric density specification.
• Ensemble physics-based ionospheric model-data assimilation modifies the vertical plasma drift and meridional F region neutral wind to produced an ensemble of ionospheric specifications for model-data inversion to reproduce TEC observations. – 3D ionospheric density specification.– Vertical plasma drift and meridional F region wind.
• Ensemble physics-based ionosphere & electric field model modifies a 3D neutral wind description to produce an ensemble of ionospheric specifications for model-data inversion to reproduce observations. – 3D ionospheric density specification.– Vertical and horizontal plasma drifts – 3D neutral wind.– Penetration electric fields
![Page 3: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/3.jpg)
Physics-based Model-Data Inversion for the LISN Region
• The LISN Model-Data inversion uses a self-consistent physics-based ionosphere & electric field model and a full neutral wind description to produce an ensemble of results for model-data inversion. – LLIONS: Low-Latitude Ionospheric Sector Model– SEF: Simple Electric Field Model– Tidal description of Neutral Winds
• E region tides – Solar diurnal, semi-diurnal (phase, magnitude)– Lunar semi-diurnal (phase, magnitude)
• F region winds– My own secret recipe for zonal winds. (HWM07 sort of)– Meridional F region winds are tidal extensions of the E region with ad hoc
additions as assimilation requires.
![Page 4: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/4.jpg)
Physics-based Models: LLIONS
• Single magnetic meridian model based on the low-latitude portion of the Ionospheric Forecast Model (IFM).
• Solves for H+, O+, NO+, O2+ , and e- densities based on
solar spectrum, neutral density, neutral winds, & vertical plasma drift.
![Page 5: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/5.jpg)
Physics-based Models: SEF• Single magnetic meridian electric field model based on a global
electric field model using field-line-integrated physics.• Solves for zonal and vertical electric fields (ExB plasma drifts)
based on conductivities and neutral winds in the magnetic meridian sector (it approx. reproduces the global model results)
![Page 6: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/6.jpg)
LLIONS-SEF Model
• Scherliess & Fejer vertical drift model and zonal drifts from Fejer.
• LLIONS-SEF with HWM 2007
• LLIONS-SEF with best tides and F region winds
![Page 7: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/7.jpg)
Methodology
LISN Sensors
Magnetometer
Dynasonde
GPS-TEC
E Region Tides
phase and magnitudes
of Hough modes
HEED
Penetration E Field
Boundary Condition
Monte Carlo generator of drivers around climatology
LISN Conditions
Optimal
Representation
Drivers
F Region Winds
cross-equator and
zonal winds
LLIONS
Drivers
Repre sentations
Drivers
Drivers
Drivers
Drivers
Repre sentations
Repre sentations
Repre sentations
Repre sentations
Optimizer
![Page 8: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/8.jpg)
Public Access to Physics-Based Processing of LISN Data
• Results to be placed at LISN data center.
• Near real-time processing by end of project.
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LISN Model-Data Study Fall 2009 Period
• Model/data study with LISN instruments–Magnetometers (electric fields)– VIPIR (F peak height & density)
• September-October used for the determination of neutral wind drivers– Electric fields & ionosphere distribution being
self-consistent with the neutral wind fields
![Page 10: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/10.jpg)
VIPER and Magnetometer DataObserved in Peruvian Sector
(Lunar Tides?)
![Page 11: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/11.jpg)
Solar & Lunar Driven Tides on Vertical Plasma Drift
![Page 12: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/12.jpg)
Neutral Winds Definition for Fall 2009
1. Used magnetometer and VIPIR observations to optimally determine tides.
2. Thermal-driven tide definition from October data. - Solar diurnal tide: (1,-2) Hough mode
3. Gravitational-driven tides definition from Fall data.– Solar semi-diurnal tide: (2,2) Hough mode– Lunar Semi-diurnal tide: (2,2) Hough mode
![Page 13: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/13.jpg)
Model Results
Scherliess & Fejer Simple Electric FieldVIPIR
![Page 14: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/14.jpg)
Does the single definition work for the whole LISN Region?
![Page 15: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/15.jpg)
Modeling Lunar Tides
![Page 16: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/16.jpg)
Conclusions for Fall 2009 Study
• Single diurnal solar tide with single definition for Solar and Lunar semi-diurnal tides provide a reasonable neutral wind driver definition to drive the low-latitude ionosphere/electric field model for the September through November 2009.
– Solar diurnal (1,-2) tide with 130 m/s magnitude with static phase.– Semi-diurnal (2,2) for both solar and lunar with identical magnitude
(65 m/s) with a static phase definition for each.
• Departures are assumed to be high-latitude inputs and/or tropospheric weather inputs into the neutral winds.
![Page 17: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/17.jpg)
LISN Model-Data Inversion
• Goal is to identify the drivers of ionosphere-electric fields in the LISN region.– Neutral wind specification is determined using an
ensemble of model runs, then use data and sim-data to determine the optimal tidal definition.
– The data-model inverstion is performed over two time scale epochs of 2 months and 1 day to obtain the periodic wind structure and the aperiod wind structure, respectively
![Page 18: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/18.jpg)
2 Time Scales - Assimilation
• Two time scales• 2 months data used to determine current epoch drivers
– Solar & Lunar gravitationally-driven semi-diurnal tides.– Solar thermal diurnal tide.– Adjustments to meridional F region wind (from Hough mode)
• 1 day data used to examine departures from long time scale driver definition– Penetration electric fields– Aperiodic winds (tropospheric weather & storm dynamo winds)
• Benefit of this approach identifies specific sources for the neutral wind structure. Rather than just the 3D neutral wind structure.
![Page 19: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/19.jpg)
Test Winter/Spring 2009
• Jicamarca Radar ISR observations available to test assimilation results (January 2009).
• GPS-TEC and magnetometer data used for
Peruvian sector for winter/spring 2009.
• Same solar & lunar tidal structure?
![Page 20: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/20.jpg)
LISN TECfor Peruvian Sector
Jan 1-15, 2009
![Page 21: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/21.jpg)
Jicamarca Radar Data Required
• The assimilation of TEC was unsuccessful.– “Best” match required zero wind velocities.– The observed very low TEC values could not be
matched.
• The LLIONS results do not match ionosphere observations during very low solar conditions– Needed to stepping back from assimilation to
examine ionization model of LLIONS – Used the Jicamarca vertical drifts to reduce
unknowns.
![Page 22: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/22.jpg)
LLIONS Model Reexamination
Jicamarca Radar Observatory2009 Jan 9-13
These data are reduced to provide Vertical drifts and zonal drifts for LLIONS.
![Page 23: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/23.jpg)
Required LLIONS Correction
• The LLIONS ionization determination requires a secondary photo electron component. This component was too large for the very low solar conditions of 2009.
• This was adjusted to produce the observed TEC values given the vertical plasma drifts observed by Jicamarca radar.
![Page 24: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/24.jpg)
JRO drifts & Best Tide Definition
• Smaller (than Fall value) gravitational tide magnitude (30 m/s).
• Smaller thermal tide magnitude (80 m/s)
• Same phases as previous study of Fall 2009
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Comparison to Magnetometer Obs
A small amplitude 4rd tidal mode reveals itself during the lunar phase where the solar and lunar gravitational tides cancel each other (5th-8th). When the lunar and solar gravitational tides constructively superimpose, then the 4th tidal mode is not apparent (10th-16th).
![Page 26: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/26.jpg)
LLIONS Adjustments for Very Low Solar Conditions
• The neutral wind tides that best matched the Jicamarca Observations were used in LLISN-SEF with the new photo electron parameterization.
• GPS-VTEC predictions are now approximately correct.• Meridional F region wind adjustment is the remaining important
adjustment for the assimilation.
![Page 27: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/27.jpg)
Current Situation of LISN Model/Data Inversion
• The LLIONS model better matches the observe TEC for very low conditions.– The lunar tidal component is smaller than
determined in the Fall 2009 study. Correction? – F region North-South wind modification will be
obtained for long scale assimilation. – Finally, perform aperiod 1-day assimilation.
![Page 28: LISN Model/Data Inversion to Determine the Drivers of the Low-Latitude Ionosphere (Comparisons with JRO ISR Drift Measurements) Vince Eccles (Modeling)](https://reader036.fdocuments.in/reader036/viewer/2022070415/56649d1a5503460f949efdf5/html5/thumbnails/28.jpg)
Summary
• The LISN model-data assimilation is performed to determine regular and aperiodic drivers of the low-latitude ionosphere.
• Doing this at two difference time-scales creates additional insight into the component drivers of the neutral wind.
• There is a possibility that a single tidal description of thermal (F10.7 dependence) and gravitational tides may capture most of the quiet time variations of ionospheric weather.