Observation of Equatorial Electrodynamics in Africa using AMBER Magnetometer Network Endawoke...
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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
Observation of Equatorial Electrodynamics in Africa using AMBER Magnetometer Network Endawoke Yizengaw Institute for Scientific Research, Boston College,
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 Yaound I, Cameroon) 2009 UN BSS
& IHY Workshop, Daejeon, Korea, 09/22/09
Slide 2
Future direction Objectives of AMBER Project Initial results
from AMBER magnetometer network Outline Why focus on Africa? 2009
UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09
Slide 3
Equatorial plasma bubble occurrence rates measured by DMSP
satellites (1989 2002) Why Africa? Burke et al., JGR, 2004
Slide 4
PAAM AF IN Fall Bubbles occurrence at different longitudinal
sectors using data from the AE-E satellite (Hei et al., 2005) Not
confirmed from the ground yet! Why Africa? 2009 UN BSS & IHY
Workshop, Daejeon, Korea, 09/22/09
Slide 5
IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09 Electron
Density, 1 Jun 08 @ 22:20 UT courtesy of Odile de La Beaujardire
Recent C/NOFS observation over Africa
Slide 6
Global Magnetometer network 2009 UN BSS & IHY Workshop,
Daejeon, Korea, 09/22/09
Slide 7
Objectives of AMBER Magnetometer Array 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. AMBER (African Meridian B-field Education
and Research) 2009 UN BSS & IHY Workshop, Daejeon, Korea,
09/22/09
Slide 8
JULIA 150-km vertical drift and magnetometer estimated drift
velocity comparison August December 2008 2009 UN BSS & IHY
Workshop, Daejeon, Korea, 09/22/09 Drift Velocity Validation
Slide 9
2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09 South
AmericaAfrica Drift velocity comparison
Slide 10
GPS_1 EARTH LEO Satellite Elevation angle GPS_2 Ionosphere
Horizon of LEO Occultation geometry Topside tomography raypath
Density response to the counter electrojet
(08/09/08)(08/04/08)(08/10/08) 2009 UN BSS & IHY Workshop,
Daejeon, Korea, 09/22/09
Slide 11
GPS TEC response to the counter electrojet TEC depleted at the
middle of the day!
Slide 12
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
Geomagnetic pulsation caused by ultra-low-frequency (ULF) wave
Slide 13
IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09 ULF wave
observation at the Equator
Slide 14
IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09
Universal Time Data Obtained on 222, 2008 Data Obtained on 223,
2008 ULF wave observation at the Equator
Slide 15
IHY-Africa 2009 meeting, Livingstone, Zambia, 06/09/09 ULF wave
and density irregularity correlation courtesy of Odile de La
Beaujardire
Slide 16
2009 UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09 ULF
wave and density irregularity correlation f(Hz) H(nT) (Reddy et
al., AG, 1994) Time series of Doppler frequency variation at three
different altitudes, observed by 54.95 MHz coherent backscatter
radar!
Slide 17
Future Direction during ISWI! 2009 UN BSS & IHY Workshop,
Daejeon, Korea, 09/22/09
Slide 18
Future Direction! Current GPS coverage Proposed to fill the gap
Augmented with 1hr LEO coverage 2hr LEO coverage 3hr LEO
coverage
Slide 19
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. Summary and Conclusion 2009
UN BSS & IHY Workshop, Daejeon, Korea, 09/22/09