Quantifying the EEJ current with ground-based ionosonde inferred vertical E × B drifts in the morning hours over Ilorin, West Africa

• Autorzy: Adeniyi, J.O. , Adimula, I.A. , Adebesin, B.O , Reinisch, B.W. , Oladipo, O.A. , Olawepo, O. , Yumoto, K.
• Języki publikacji: EN

Abstrakty

EN

The relationship between the ground-based inferred vertical E × B drifts, Vz, and the magnetic equatorial electrojet current during the year of solar minima was presented. Both the diurnal and seasonal Vz variations are positively directed during the daytime and negative at nighttime. The evening time pre-reversal enhancement occurs around 19:00 LT. The fairly strong linear relationship between the electrojet current strength and Vz exhibited higher correlations during the daytime (06:00-16:00 LT). The maximum morning time proxy parameter described by E = [d (ΔHILR)/dt]max in the morning hours, indicating the east-west electric field in the EEJ, corresponds reasonably well with the E × B drift and, hence, can be used as a proxy parameter for representing Vz in the morning hours. The daytime EEJ magnitude seasonal changes are connected with a change in conductivity emerging from the action of turbulence and divergence of momentum flux. These waves above the dynamo region are suggested to lead to partial counter electrojet during the equinoctial months.

Słowa kluczowe

PL

pole elektryczne

EN

electric field; pre-reversal enhancement; equatorial electrojet; E × B drifts; counter electrojet

• Czasopismo: Acta Geophysica
• Rocznik: 2014
• Tom: Vol. 62, no. 3
• Strony: 656--678
• Opis fizyczny: Bibliogr. 31 poz.

Twórcy

autor

Adeniyi, J.O.

• Department of Physics, University of Ilorin, Ilorin, Nigeria

autor

Adimula, I.A.

• Department of Physics, University of Ilorin, Ilorin, Nigeria

autor

Adebesin, B.O

• Department of Industrial Physics, Landmark University, Omu-Aran, Kwara State, Nigeria,

autor

Reinisch, B.W.

• Lowell Digisonde International, LLC, Lowell, USA

autor

Oladipo, O.A.

• Department of Physics, University of Ilorin, Ilorin, Nigeria

autor

Olawepo, O.

• Department of Physics, University of Ilorin, Ilorin, Nigeria

autor

Yumoto, K.

• Space Environment Research Center, Kyushu University, Fukuoka, Japan

Bibliografia

• Abdu, M.A., G.O. Walker, B.M. Reddy, E.R. de Paula, J.H.A. Sobral, and B.G. Fejer (1993), Global scale equatorial ionization anomaly (EIA) response to magnetospheric disturbances based on the May-June 1987 SUNDIALcoordinated observations, Ann. Geophys. 11, 7, 585-594.
• Abdu, M.A., T.K. Ramkumar, I.S. Batista, C.G.M. Brum, H. Takahasi, B.W. Reinisch, and J.H.A. Sobral (2006), Planetary wave signatures in the equatorial atmosphere-ionosphere system, and mesosphere – E- and F-region coupling, J. Atmos. Sol.-Terr. Phys. 68, 3-5, 509-522, DOI: 10.1016/j.jastp.2005.03.019.
• Adebesin, B.O. (2008), Roles of interplanetary and geomagnetic parameters in “intense” and “very intense” magnetic storms generation and their geoeffectiveness, Acta Geod. Geophys. Hu. 43, 4, 383-408, DOI: 10.1556/AGeod.43.2008.4.2.
• Adebesin, B.O., S.O. Ikubanni, S.J. Adebiyi, and B.W. Joshua (2013a), Multi-station observation of ionospheric disturbance of March 9, 2012 and comparison with IRI-model, Adv. Space. Res. 52, 4, 604-613, DOI: 10.1016/j.asr2013.05.002.
• Adebesin, B.O., J.O. Adeniyi, I.A. Adimula, and B.W. Reinisch (2013b), Equatorial vertical plasma drift velocities and electron densities inferred from groundbased ionosonde measurements during low solar activity, J. Atmos. Sol.-Terr. Phys. 97, 58-64, DOI: 10.1016/j.jastp.2013.02.010.
• Adebesin, B.O., J.O. Adeniyi, I.A. Adimula, and B.W. Reinisch (2013c), Low latitude nighttime ionospheric vertical E × B drifts at African region, Adv. Space Res. 52, 12, 2226-2237, DOI: 10.1016/j.asr.2013.09.033.
• Adebesin, B.O., J.O. Adeniyi, I.A. Adimula, B.W. Reinisch, and K. Yumoto (2013d), F2 layer characteristics and electrojet strength over an equatorial station, Adv. Space Res. 52, 5, 791-800, DOI: 10.1016/j.asr.2013.05.025.
• Adeniyi, J.O. (1986), Magnetic storm effects on the morphology of the equatorial F2-layer, J. Atmos. Sol.-Terr. Phys. 48, 8, 695-702, DOI: 10.1016/0021-9169(86)90019-X.
• Adimula, I.A., A.B. Rabiu, Y. Yumoto, and the MAGDAS Group (2011), Geomagnetic field variations from some equatorial electrojet stations, Sun Geosphere 6, 2, 45-49.
• Anderson, D., A. Anghel, K. Yumoto, M. Ishitsuka, and E. Kudeki (2002), Estimating daytime vertical E × B drift velocities in the equatorial F-region using ground-based magnetometer observations, Geophys. Res. Lett. 29, 12, 37-1-37-4, DOI: 10.1029/2001GL014562.
• Anderson, D., A. Anghel, J.L. Chau, and O. Veliz (2004), Daytime vertical E × B drift velocities inferred from ground-based magnetometer observations at low latitudes, Space Weather 2, 11, S11001, DOI: 10.1029/2004SW000095.
• Anderson, D., E. Araujo-Pradere, and L. Scherliess (2009), Comparing daytime, equatorial E × B drift velocities and TOPEX/TEC observations associated with the 4-cell, non-migrating tidal structure, Ann. Geophys. 27, 2861-2867, DOI: 10.5194/angeo-27-2861-2009.
• Araujo-Pradere, E.A., D.N. Anderson, M. Fedrizzi, and R. Stoneback (2010), Quantifying the daytime, equatorial E × B drift velocities at the boundaries of the 4-cell tidal structure using C/NOFS’ CINDI observations. In: P. Doherty, M. Hernández-Pajares, J.M. Juan, J. Sanz, and A. Aragon-Angel (eds.), Proc. Int. Beacon Satellite Symposium 2010, 7-11 June 2010, Barcelona, Spain.
• Bolaji, O.S., A.B. Rabiu, I.A. Adimula, J.O. Adeniyi, and K. Yumoto (2011), Interhemispheric trans-equatorial field-aligned currents deduced from MAGDAS at equatorial zone, Space Res. J. 4, 1, 12-22, DOI: 10.3923/srj.2011.12.22.
• Devasia, C.V., V. Sreeja, and S. Ravindran (2006), Solar cycle dependent characteristics of the equatorial blanketing Es layers and associated irregularities, Ann. Geophys. 24, 11, 2931-2947.
• Fang, T.W., A.D. Richmond, J.Y. Liu, A. Maute, C.H. Lin, C.H. Chen, and B. Harper (2008), Model simulation of the equatorial electrojet in the Peruvian and Philippine sectors, J. Atmos. Sol.-Terr. Phys. 70, 17, 2203-2211, DOI: 10.1016/j.jastp.2008.04.021.
• Fejer, B.G., and L. Scherliess (1997), Empirical models of storm time equatorial zonal electric fields, J. Geophys. Res. 102, A11, 24047-24056, DOI: 10.1029/97JA02164.
• Fejer, B.G., E.R. de Paula, S.A. González, and R.F. Woodman (1991), Average vertical and zonal F region plasma drifts over Jicamarca, J. Geophys. Res. 96, A8, 13901-13906, DOI: 10.1029/91JA01171.
• Fritts, D.C., and M.J. Alexander (2003), Gravity wave dynamics and effects in the middle atmosphere, Rev. Geophys. 41, 1, 1003, DOI: 10.1029/2001RG000106.
• Huang, X., and B.W. Reinisch (1996), Vertical electron density profiles from Digisonde ionograms. The average representative profile, Ann. Geophys. 39, 4, 751-756, DOI: 10.4401/ag-4010.
• Liu, L., W. Wan, Y. Chen, and H. Le (2011), Solar activity effects of the ionosphere: A brief review, Chinese Sci. Bull. 56, 12, 1202-1211, DOI: 10.1007/s11434-010-4226-9.
• Oyekola, O.S., and L.B. Kolawole (2010), Equatorial vertical E × B drift velocities inferred from ionosonde measurements over Ouagadougou and the IRI-2007 vertical ion drift model, Adv. Space Res. 46, 5, 604-612, DOI: 10.1016/j.asr.2010.04.003.
• Rabiu, A.B., A.I. Mamukuyomi, and E.O. Joshua (2007), Variability of equatorial ionosphere inferred from geomagnetic field measurements, Bull. Astron. Soc. India 35, 4, 607-618.
• Radicella, S.M., and J.O. Adeniyi (1999), Equatorial ionospheric electron density below the F2 peak, Radio Sci. 34, 5, 1153-1163, DOI: 10.1029/1999RS900071.
• Scherliess, L., and B.G. Fejer (1999), Radar and satellite global equatorial F region vertical drift model, J. Geophys. Res. 104, A4, 6829-6842, DOI: 10.1029/1999JA900025.
• Sreeja, V., C.V. Devasia, S. Ravindran, and T.K. Pant (2009), Observational evidence for the plausible linkage of Equatorial Electrojet (EEJ) electric field variations with the post sunset F-region electrodynamics, Ann. Geophys. 27, 4229-4238, DOI: 10.5194/angeo-27-4229-2009.
• Uemoto, J., T. Maruyama, S. Saito, M. Ishii, and R. Yoshimura (2010), Relationships between pre-sunset electrojet strength, pre-reversal enhancement and equatorial spread-F onset, Ann. Geophys. 28, 2, 449-454, DOI: 10.5194/angeo-28-449-2010.
• Vineeth, C., T.K. Pant, and M.M. Hossain (2012a), Enhanced gravity wave activity over the equatorial MLT region during counter electrojet events, Indian J. Radio Space Phys. 41, 2, 258-263.
• Vineeth, C., T.K. Pant, K.K. Kumar, L. Jose, S.G. Sumod, and S. Alex (2012b), Counter equatorial electrojet: Analysis of the variability in daytime mesopause temperature and winds, J. Atmos. Sol.-Terr. Phys. 75-76, 115- 121, DOI: 10.1016/j.jastp.2011.07.005.
• Woodman, R.F., J.L. Chau, and R.R. Ilma (2006), Comparison of ionosonde and incoherent scatter drift measurements at the magnetic equator, Geophys. Res. Lett. 33, 1, L01103, DOI: 10.1029/2005GL023692.
• Yumoto, K., and the MAGDAS Group (2007), Space weather activities at SERC for IHY: MAGDAS, Bull. Astron. Soc. India 35, 4, 511-522.

Identyfikatory

DOI

10.2478/s11600-014-0202-0