Schunk, R. W.

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Ionosphere: Past, Present and FutureProblemsR.W. SchunkCenter for Atmospheric & Space SciencesUtah State UniversityLogan, Utah  84321CEDAR MeetingJune 23, 2006Outline• Ionospheric Environment• Status• High Latitudes• Middle Latitudes• Low Latitudes• SummaryIonospheric EnvironmentF-Region     O+hν → O++e*     O++N2 → NO++N     O++O2 → O2++OTopside     O++H ⇔ H++OO+H+ue + corotationcorotationBcorotation + ueDiffusion and Wind-Induced Flow Along BSojka and Schunk (1979)Ionospheric Variations• Altitude• Latitude• Longitude• Universal Time• Season• Solar Cycle• Geomagnetic ActivityStatus• Ionosphere has both a Background State(Climatology) and a Disturbed State (Weather)• Climatology is Basically Understood• Weather Involves Storms, Substorms, PlasmaStructures, Wave Activity, and PlasmaInstabilities• Main Research Focus is on WeatherHigh LatitudesLyons (1992)Polar WindF-Region ConvectionE-Region CurrentsSchunk (1983)Volland Model2-cell Pattern,  ΔΦ=40 kV,  No CorotationE⊥ BE⊥×BSojka et al. (1979)Geographic Inertial FrameSojka et al. (1979)High Latitude ClimatologyBrinton et al., 1978Storms and Substorms• Ionosphereo Increased Convection Speedso Increased Joule and Particle Heatingo O+ →  NO+o Ti →  Ti|| , Ti⊥• Thermosphereo Gravity Waveso O/N2 Changeso Enhanced Windso Supersonic Windso Anisotropic TnSatellite Images• Ground Photograph by Jan Curtis.• FUV Image from the IMAGE Satellite.Burch, J. L., Scientific American, 284, 72-80, 2001• Bastille Day Storm• July 14-15, 2000• Snapshots During a 1-Hour PeriodSatellite ImagesIonosphere Forecast ModelIonosphere Forecast ModelNeutral Gas ExpansionIon Polar WindEnergizedIonsPolar WindCuspElectronse- J||J||e-PhotoelectronsEARTHO+     6 UTDemars and Schunk (2003)H+     6 UTDemars and Schunk (2003)Neutral Polar WindGardner and Schunk (2004)Neutral Polar WindGardner and Schunk (2004)Noon-Midnight Meridian Flux 6:10 UTH+ O+OsHsCauses of Plasma Structures• Changes in the Solar Wind Drivers• Structured Electric Fields• Structured Particle Precipitation• Time Variations in E-fields and Precipitation• Time Delays and Feedback Mechanisms in the M-I-T System• Plasma InstabilitiesGreenland100-300 km      by1000-3000 kmValladares et al (1994)Mesoscale Ionospheric Structures• Propagating Plasma Patches• Propagating Atmospheric Hole• Propagating Polar Wind Jets• Propagating Neutral Streams• Sun-Aligned Polar Cap Arcs• Theta Aurora• Boundary and Auroral Blobs• Stationary Polar Wind Jets• Neutral Polar Wind Streams• Sub-Auroral Ion Drift Events (SAID)• Storm Enhanced Densities (SED) RidgesPropagating Plasma Patches• Mesoscale Regions of Enhanced Plasma Density• Created in or Equatorward of Noon Auroral Zone• Antisunward Convection with Background Plasma• Horizontal Extent of  200 - 1000 km• Circular or Cigar-Shaped• Single or Multiple Patches• Density Enhancement of  Few % to Factor 100• Enhancement Extends Along BSingle, Circular, Propagating Plasma Patch• Gaussian Patch Distribution - 1000 km• Peak Ne Factor 5 Above Background• F10.7 = 150, Winter Polar Region• Quiet Conditions, then Southward IMF & 100 kV at TimePlasma Patch Imposed• Collisional Snowplow• Nn Depletion in and Behind Patch, Enhancement in Front• Increased Un in Patch• Neutral Gas Upwelling and O/N2 Changes• Disturbance Moves Along with Patcht = 0 t = 1 hr∆Tn ∆Un∆NNe300 kmQaanaaq, Greenland,  October 29, 1989All-Sky Images (630 nm)2 - Minute IntervalNeutral DensityPerturbationNeutral Gas Perturbations300 km• Single, Circular, Propagating Plasma Patcho ρn ~ 30-35 %o Tn ~ 100 - 300 Ko Un ~ 100 m/s• Multiple, Cigar-Shaped, Propagating Plasma Patcheso ρn ~ 30 %o Tn ~ 100 - 400 Ko Un ~ 150 m/s• Comparable to Day-Night Change in the Thermosphere atMid-LatitudesMSIS ThermosphereNoon-Midnight Variation at 300 kmMid-Latitudes• Solar Minimum, Winter Solsticeρn ~ 40 %Tn ~ 45 K• Solar Maximum, Summer Solsticeρn ~ 50 %Tn ~ 250 KPropagating Polar Wind JetEnergizedIonsPolar WindCuspElectronse- J||J||e-PhotoelectronsEARTHSchunk et al (2004)Mid-LatitudesInterhemisphere FlowSolsticeday nightEvans and Holt (1978)Cluster MissionPlasma Density StructuresTransverse Equatorial Size 20-5000 km Darrouzet et al (2006)Gauss-Markov Kalman Filter ExampleGlobal Assimilation of Ionospheric MeasurementsUtah State University, (435)797-2962, schunk@cc.usu.edu;Universities of Colorado (Boulder), Texas (Dallas), and Washington“Bringing the pieces together” November 16, 2003 GPS Ground TEC measurements from more than   900 GPS Receivers (from SOPAC Data Archive) Includes Receivers from: IGS CORS EUREF and othersClimateKalman FilterMore than 3000SlantTEC Measurementsare assimilated every15 minutes.Global Assimilation of Ionospheric MeasurementsUtah State University, (435)797-2962, schunk@cc.usu.edu;Universities of Colorado (Boulder), Texas (Dallas), and Washington“Bringing the pieces together”Gauss-Markov Kalman Filter ReconstructionGauss-Markov Kalman Filter ExampleRegional ModeGlobal Assimilation of Ionospheric MeasurementsUtah State University, (435)797-2962, schunk@cc.usu.edu;Universities of Colorado (Boulder), Texas (Dallas), and Washington“Bringing the pieces together” 3-D Ionospheric Ne Reconstruction over North AmericaLarge Geomagnetic Storm on November 20-21, 2003 GPS Ground TEC Measurements from more than    300 GPS Receivers (CORS GPS Network + other)    over the continental US and Canada 2 Ionosondes at Dyess and Eglin Observe large TEC Enhancements over the Great    Lakes during November 20, 2003 @ 2000 UT.Global Assimilation of Ionospheric MeasurementsUtah State University, (435)797-2962, schunk@cc.usu.edu;Universities of Colorado (Boulder), Texas (Dallas), and Washington“Bringing the pieces together”Kalman FilterClimateAbout 2000 Slant TEC Values are Assimilated every 15 minSchunk et al. (2005)Foster et al (2004)Low-Latitude Ionosphere• Equatorial Anomaly• Ne Variability• Spread-F/Plasma Bubbles• Rayleigh-Taylor InstabilitySnapshot of modeled electron densities at 300 km and 12 UT displayed in a geographiccoordinate system.  The electron densities were calculated from the Ionosphere-PlasmasphereModel (IPM) and are shown along geomagnetic field lines.IGRF Magnetic FieldEffects of Diffusion, Electric Fields, andWinds on the Low-Latitude IonosphereF-region Ionization Transport Process With theTransequatorial WindEquatorial FountainHanson and Moffett (1966)Low Latitude Climatology• International Reference Ionosphere (IRI)• foF2 for solar Maximum, Equinox and UT=0Bilitza et al. (1993)GPS/MET SatelliteEquatorial Profiles-5° ≤ θ ≤ 5°1200 < local time < 1400-5° ≤ θ ≤ 5°2000 < local time < 2200Equatorial Plasma Bubbles• Vertically Elongated Wedges of Depleted Plasma• Entire North - South Extent of B Depleted• Up to Factor 1000 Depletion• Bubble Apex Altitudes Between 500 - 1500 km• Typical Bubbles:  100-500 m/s up• Fast Bubbles:  500 m/s - 5 km/s up      1 km/s horizontalSpread F/Equatorial BubblesArgo and Kelley (1986)Equatorial Spread-F and BubblesJULIA Coherent Scatter RadarHysell and Burcham (1998)• DMSP F10 Satellite• 234 E Longitude,  19.7 MLT,  117 SZA,  750 km Orbit• Typical Bubbles:  100-500 m/s up• Fast Bubbles:  500 m/s - 5 km/s up      1 km/s horizontalNeutral Density(top) andTemperature(bottom)Perturbationsdue to 4 PlasmaBubbles300 kmGolden Age of Aeronomy• Large Amount of Data Available• Access via Virtual Observatories• Data Assimilation Models• Coupled Physics-Based Geospace Models• Community Coordinated Modeling Center (CCMC)• Elucidating Mass, Momentum, and Energy Coupling in theM-I-T System at Global, Regional, and Local Scales willbe Possible• Rigorous Inclusion of Instabilities in Global Models willbe Possible

Ionosphere: Past, Present and Future Problems

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Ionosphere: Past, Present and Future Problems

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