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Observation of Equatorial Electrodynamics in Africa using AMBER Magnetometer Network

Observation of Equatorial Electrodynamics in Africa using AMBER Magnetometer Network. Endawoke Yizengaw Institute for Scientific Research, Boston College, USA. Mark Moldwin (Michigan University, USA), Alem Mebrahtu (Mekelle University, Ethiopia),

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Observation of Equatorial Electrodynamics in Africa using AMBER Magnetometer Network

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  1. Observation of Equatorial Electrodynamics in Africa using AMBER Magnetometer Network Endawoke Yizengaw Institute for Scientific Research, Boston College, USA Mark Moldwin (Michigan University, USA), Alem Mebrahtu (Mekelle University, Ethiopia), Baylie Damtie (Bahir Dar University, Ethiopia), Fatma Anad (CRAAG, Algeria), and Cesar Mbane Biouele(University of Yaoundé I, Cameroon) 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  2. Outline • Why focus on Africa? • Objectives of AMBER Project • Initial results from AMBER magnetometer network • Future direction 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  3. Why Africa? Burke et al., JGR, 2004 Equatorial plasma bubble occurrence rates measured by DMSP satellites (1989 – 2002)

  4. Why Africa? Bubbles occurrence at different longitudinal sectors using data from the AE-E satellite (Hei et al., 2005) AF PA AM IN Fall Fall Not confirmed from the ground yet! Fall 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  5. Recent C/NOFS observation over Africa Electron Density, 1 Jun 08 @ 22:20 UT courtesy of Odile de La Beaujardière IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09

  6. Global Magnetometer network 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  7. Objectives of AMBER Magnetometer Array AMBER (African Meridian B-field Education and Research) To address two fundamental areas of space physics: • the processes governing electrodynamics of the equatorial ionosphere as a function of local time, longitude, magnetic activity, and season, and • ULF pulsation strength and its connection with equatorial electrojet strength at low/mid-latitude regions. 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  8. Drift Velocity Validation JULIA 150-km vertical drift and magnetometer estimated drift velocity comparison August –December 2008 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  9. Drift velocity comparison Africa South America 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  10. Density response to the counter electrojet GPS_1 Elevation angle Topside tomography raypath GPS_2 Occultation geometry LEOSatellite Ionosphere EARTH Horizon of LEO (08/04/08) (08/09/08) (08/10/08) 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  11. GPS TEC response to the counter electrojet TEC depleted at the middle of the day! 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  12. Geomagnetic pulsation caused by ultra-low-frequency (ULF) wave • Toroidal and poloidal (compressional) mode of ULF waves • Toroidal and compressional mode have north-south and east-west electric field perturbation in the ionosphere when it mapped along the field line, respectively. • Toroidal mode can only have pointing vector along the magnetic field; while compressional mode have pointing vector both in the parallel and perpendicular directions of the magnetic field. • The compressional ULF wave can propagate all the way down to the equatorial ionosphere right across the magnetic field. 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  13. ULF wave observation at the Equator IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09

  14. ULF wave observation at the Equator Data Obtained on 222, 2008 Data Obtained on 223, 2008 Universal Time IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09

  15. ULF wave and density irregularity correlation courtesy of Odile de La Beaujardière IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09

  16. ULF wave and density irregularity correlation f(Hz) H(nT) Time series of Doppler frequency variation at three different altitudes, observed by 54.95 MHz coherent backscatter radar! (Reddy et al., AG, 1994) 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  17. Future Direction during ISWI! 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  18. Future Direction! Current GPS coverage Proposed to fill the gap Augmented with 1hr LEO coverage 2hr LEO coverage 3hr LEO coverage 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  19. Summary and Conclusion • In conclusion, such multi-instrument observations in the African longitudinal sector, a region that has been devoid from ground-based instruments, will provide excellent opportunity to the scientific community to understand clearly the physics behind the unique ionospheric irregularities that has been often observed by flyby LEO satellites. • The preliminary results presented here clearly shows that the ideal locations of AMBER magnetometers will play a key role in estimating the electrodynamics that control the equatorial ionospheric irregularities. 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  20. Thank You! 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  21. MALI GPS station on August 09, 2008 No major scintillation activity 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  22. PUER GPS station on August 09, 2008 No major scintillation activity 2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09

  23. ULF wave observation at the Equator IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09

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