Physics Journal
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Physics Journal, Vol.1, No.2, Sep. 2015, Pub. Date: Sep. 1, 2015
Characterizing the Maximum Electron Density of the F2 Layer (NmF2) in the Equatorial Ionosphere
Pages: 137-152 Views: 2196 Downloads: 1021
[01] A. Ogwala, Department of Physics, Lagos State University, Ojo, Lagos.
[02] E. O. Somoye, Department of Physics, Lagos State University, Ojo, Lagos.
[03] E. O. Onori, Department of Physics, Lagos State University, Ojo, Lagos.
[04] R. A. Adeniji-Adele, Department of Physics, Lagos State University, Ojo, Lagos.
A study of the Maximum Electron Density of the F2 layer (NmF2) in the ionosphere over the African, Asian and American sectors is presented. Mean NmF2 and NmF2 coefficient of variability (CV) of three ionosonde stations namely Dakar (14.8°N, 17.4°, 16.1°N dip) in the African sector, Manila (14.7°N, 121.1°E, 14.2°N dip) in the Asian sector and Huancayo (12°S, 75.3°W, 1.9°N dip) in the American sector were used for this study during three epochs of solar cycle: 1982, year of high solar activity (HSA) with monthly average sunspot number, Rz12 (115.9), 1983, year of moderate solar activity (MSA) with monthly average sunspot number, Rz12 (68.7) and 1986, year of low solar activity (LSA) with monthly average sunspot number, Rz12 (13.4). Results obtained show that pre- and post-noon peaks bothering the noon bite-out were present in the diurnal curves of mean NmF2 for the three stations. Morning peaks were predominant during HSA while afternoon peaks were predominant during MSA and LSA. NmF2 CV is characterized by pre- and post-midnight peaks in all the three stations. The results reveal diurnal, seasonal, solar cycle and longitudinal influences of mean NmF2 and NmF2 CV.
Mean NmF2, NmF2 CV, Diurnal, Seasonal, Solar Activity, Noon Bite-Out
[01] Adeniyi, JO. A Study of some features of the equatorial ionosphere on magnetically quiet and disturbed days. [PhD Thesis]. Ibadan, University of Ibadan, 1980.
[02] Akala, AO, Oyeyemi, EO, Somoye, EO, Adeloye, AB, Adewale, AO. Variability of foF2 in the African equatorial ionosphere. Advances in Space Research, 2010a; 45: 1311-1314.
[03] Akala, AO, Adeloye, AB, Somoye, EO. Ionospheric foF2 variability over the Southeast Asian sector. J. Geo. Res., 2010b; Vol. 115, A09329, doi: 10.1029/2010JA015250.
[04] Akala AO, Somoye EO Adeloye AB, Rabiu AB. Ionospheric foF2 variability at equatorial and low Latitudes during high, moderate and low solar activity. Indian J. Radio and Space Physics, 2011; 40: 124-129.
[05] Appleton E V. Two anomalies in the ionosphere, Nature, 1946; 157, 691.
[06] Araujo-Pradere EA, Fuller-Rowell TJ, Codrescu MV, Bilitza D. Characteristics of the ionospheric variability as a function of season, latitude, local time and geomagnetic activity. Radio Science. 2005; 40: RS5009, doi: 10.1029/2004RS003179.
[07] Basu S, Groves KM, Basu Su, Sultan JP. Specification and forecasting of scintillations in communication/Navigation links: current status and future plans. J. Atmos. Solar-Terr. Phys. 2002; 64: 1745 - 1754.
[08] Bilitza D, Obrou OK, Adeniyi JO, Oladipo O. Variability of foF2 in the equatorial ionosphere. Advances in Space Research, 2004; 34: 1901-1906.
[09] Chou YT, Lee CC. Ionospheric variability at Taiwan low latitude station: comparison between observations and IRI-2001 model. Adv. Space Res. 2008; 42: 673–681.
[10] Coley WR, Mc Clure JP, Hanson WB. Equatorial fountain effect and dynamo drift signatures from AE-E observations. J. Geophys. Res., 1990; 95: 21285 – 21290.
[11] Forbes JM, Palo SE and Zhang X. Variability in the ionosphere. J. Atmos. and Solar-Terr. Phys., 2000; 62: 685-693.
[12] Fotiadis DN, Baziakos GM, Kouris SS. On the global behaviour of the day- to- day MUF variation. Adv. Space Res. 2004; 33(6): 893-901.
[13] Hanson WB and Moffet RJ. Ionization transport effects in the equatorial F region. J. Geophys. Res., 1966; 71: 5559 – 5572.
[14] Heredia T and Elias AG. Diurnal variation of NmF2 associated with E×B drift at the equator during solar maxima. Geofisica Internacional, 2004; 43(1): 119 – 124.
[15] Kouris SS, Fotiadis DN. Ionospheric variability a comparative statistical study. Adv. Space Res. 2002; 29 (6): 977-985.
[16] Liu H and Watanabe S. Seasonal variation of the longitudinal structure of the equatorial ionosphere: Does it reflect tidal influences from below? J. Geophys. Res., 2008; 113, A08315, doi: 10.1029/2008JA013027.
[17] Miller KL, Lemon M and Richards PG. A meridional wind climatology from a fast model for the derivation of meridional wind from the height of the ionospheric F2 layer J. Atmos. Terrs. Phys., 1997; 59: 1805-1822.
[18] Namba S and Maeday KI. Radio Wave Propagation, 1939; 86 pp., Corona Publishing, Tokyo.
[19] Rajaram G and Rastogi RG. Equatorial electron densities - seasonal and solar cycle changes, J. Atmos. Terrs. Phys., 1977; 39: 1175-1182.
[20] Rishbeth H. The equatorial F-layer: Progress and puzzles, Ann. Geophys., 2000; 18, 730–739.
[21] Schunk RW. Ionospheres Physics, Plasma Physics and Chemistry, Cambridge University Press, UK, 2000; pp 554.
[22] Somoye EO. Periodicity of solar cycle from diurnal variations of foF2 at Ibadan. International J. Physical Sciences. 2009a; 4(3): 111-114.
[23] Somoye EO. (2009b). Comparison of NmF2 variability at Ibadan, Singapore and Slough during different epochs of solar cycle. Asian J. of Sci. Res., 2009b; 2(3): 155-160.
[24] Somoye EO, Akala AO. NmF2 Variability at Equatorial and Low Latitude Stations: A review, Research Journal of Physics 2010; 4(2): 50 – 55.
[25] Somoye EO, Akala AO. Comparison of diurnal, seasonal and latitudinal effect of MUF VR and NmF2 VR during some solar cycle epochs. J. Adv. Space Res., 2013; 47: 2182 – 2187.
[26] Somoye EO, Akala AO, Ogwala A. Day to day variability of h’F and foF2 during some solar cycle epochs, J. Atmos. Terr. Phys., 2011; 73, 1915 – 1922.
[27] Somoye EO, Akala AO, Adeniji-Adele RA, Iheonu EE, Onori EO, Ogwala A.. Equatorial F2 characteristics variability: a review of recent observations. J. Adv. Space Res., 2013; 52 (7): 1261 – 1266.
[28] Yizengaw E. Ionosphere: Plasmasphere: Magnetosphere: Space Weather [Internet] 2013 [updated 2013 May 20; cited 2014 Oct 14, Available from:
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