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AN ELECTRON DENSITY PROFILE MODEL FOR THE SOUTH AFRICAN IONOSPHERE

AN ELECTRON DENSITY PROFILE MODEL FOR THE SOUTH AFRICAN IONOSPHERE. Lee-Anne McKinnell. Physics Department, Rhodes University, Grahamstown, South Africa Space Physics Group, Hermanus Magnetic Observatory (HMO), Hermanus, South Africa. South African Ionosonde Network. 2000 – 2008.

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AN ELECTRON DENSITY PROFILE MODEL FOR THE SOUTH AFRICAN IONOSPHERE

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  1. AN ELECTRON DENSITY PROFILE MODEL FOR THE SOUTH AFRICAN IONOSPHERE Lee-Anne McKinnell Physics Department, Rhodes University, Grahamstown, South Africa Space Physics Group, Hermanus Magnetic Observatory (HMO), Hermanus, South Africa

  2. South African Ionosonde Network 2000 – 2008 (22.4ºS, 30.9ºE ) Madimbo 2000 – 2008 Louisvale (28.5ºS,21.2ºE) 1973 – 2008 N(h) profiles from 1996 Installed June 2008 Grahamstown (33.3ºS, 26.5ºE) Hermanus (34.4ºS, 19.2ºE)

  3. Neural Networks Training a computer to learn the relationship between a given set of inputs and a corresponding output highly suitable for non-linear relationships Main requirement -- an archived database describing the history of the relationship South African region  Grahamstown, n(h) profile data from 1996, characteristics from 1973  Louisvale & Madimbo, n(h) profile data from 2000

  4. Special Features Criterion for optimisation • F1 Probability Network • Smoothing technique • rms error on individual parameters • Ability to reproduce realistic profiles SABIM Model • South African region • Bottomside ionospheric model • Electron density profile • Several NNs combined

  5. Solar Activity

  6. SABIM South African Bottomside Ionospheric Model Model Geomagnetic position info Day Number Hour Electron Density Profile Solar Activity Magnetic Activity Neural Network based empirical ionospheric model for the South African region

  7. The Model E layer Profile F layer Profile Determining the probability of an F1 layer F1 Probability NN Output determines 1) or 2) or 3) Is E layer predictable? E limits NN Predict E layer foE, hmE, E profile NNs F1 Layer Network Included Peak parameters – foF1, hmF1 Chebyshev coefficients Profile constructed L-algorithm, weighted avg btn F1 and No F1 F2 Layer Network Included Peak parameters – foF2, hmF2 Chebyshev coefficients Profile constructed foF2 – global foF2 network used 1) No F1 layer F2NN 2) F1 layer definite F1F2NN 3) F1 layer in L condition L Algorithm Smoothing Technique

  8. Diurnal foF2 variations

  9. foF1 variations foF1 2007 10h00 UT

  10. foE variations foE 2007 10h00 UT

  11. Predicted profiles

  12. 10h00 UT Contour Plots foE foF1 Summer hmE hmF1

  13. 10h00 UT Contour Plots foE foF1 Winter hmE hmF1

  14. 10h00 UT Contour Plots Summer foF2 hmF2 foF2 hmF2 Winter

  15. F1 Probability

  16. Uncertainty

  17. Future Plans • extend SABIM to include Hermanus data • update every 2 years • use manually obtained F1 information for F1 probability network • expand uncertainty network

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