We describe here for the first time the morphology of the equatorial electrojet eej in the central. The daytoday variability of the equatorial electrojet in peru. Phase variability of sq h on normal quiet days in the. From a study of abnormal quiet days aqds at equatorial latitudes it was found earlier sastri that the occurrence of an abnormal sqh phase confined to the equatorial electrojet belt is closely associated with the incidence of complete or partial counter electrojet cej conditions marked daytime depressions in the h field in the electrojet.
It has been known for many decades that the lunar tidal influence in the equatorial electrojet eej is noticeably enhanced during northern hemisphere winters. Characteristics of the equatorial electrojet determined from. Swarm european space agency esas satellite constellation swarm consists of three satellites, namely, swarm. Our analysis of the equatorial electrojet variations obtained from the magnetic swarm data indicates that the stormtime penetration electric fields were, most likely, the main driver of the observed ionospheric.
Vhf radio communications beyond the horizon using forward scatter from the equatorial electrojet martin f. Effect of sudden stratospheric warming on lunar tidal. The typical quiet day variations of the equatorial electrojet eej current intensity with time of the day, season, sunspot number, and geomagnetic latitude are presented in terms of the. Equatorial electrojet 1st edition c agodi onwumechikli. Conductivity, electric field and electron drift velocity within the equatorial electrojet by r. Pdf the field of the equatorial electrojet from champ data. Ionospheric eregion irregularities du1ing equatorial. Two mechanisms can efficiently amplify thermal density fluctuations in the equatorial electrojet eej.
Equatorial electrojet studies from rocket and ground. The complete spectrum of the equatorial electrojet related. These mechanisms result from plasma instabilities known as the twostream instability and the gradient drift also known as the crossfield instability, discussed in detail in kelley 1989, 2009. Vhf radio communications beyond the horizon using forward. Crosssectional profile determination of equatorial electrojet for various longitudes along dip equator using set of gauss coefficients for earths magnetic. The crosssectional profile of the equatorial electrojet is deter mined for various longitudes dong the dip equator, uehg a set of 48 gauss coefficients for the earths magnetic field. They concluded that it is the lunar semidiurnal tide that is amplified by ssw and modulates the lowlatitude and midlatitude ionosphere. At the magnetic dip equator, where the magnetic field. Relation between stratospheric sudden warming and the. An electrojet is an electric current which travels around the e region of the earths ionosphere.
Pdf the equatorial anomaly in ionospheric total electron. The typical quiet day variations of the equatorial electrojet eej current intensity with time of the day, season, sunspot. Gps receivers except for the station brasilia braz, which is downloaded from. This phenomenon was ascribed by chapman 1951 as due to an eastward band of electric current in the ionosphere, which he named the equatorial electrojet. Conductivity, electric field and electron drift velocity. This file contains additional information such as exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. Equatorial electrojet download ebook pdf, epub, tuebl, mobi. Equatorial electrojet over west africa from ground and.
A number of studies in recent years have reported about the lunar tidal enhancements in the equatorial electrojet eej from ground and spacebased magnetometer measurements during. Abstract the equatorial electrojet eej is a narrow band of current flowing eastward. Variability of the critical frequency fof2 for equatorial. Relationship between lunar tidal enhancements in the. Compliance with the equator principles gps ucsd university of. Characteristics of the equatorial electrojet current in the central. Rocketborne insitu measurements of electron density and current density made from thumba, india, on four occasions between 1966 and 1973 and on one flight from peru in 1965 are. Plotting the latitudinal variations of the daily range of h at six low. Combining the data of insitu measurements of ionospheric current, j m by rocketborne instruments and the ground based geomagnetic h field close to the magnetic equator a. Pdf geomagnetic stormtime variations often occur coherently at high.
Characteristics of the equatorial electrojet current in. Longitudinal dependence of equatorial irregularities and electrodynamics. Longitudinal variation of the lunar tide in the equatorial. On the daytoday variation of the equatorial electrojet. Equatorial electrojet model eejm2 the equatorial electrojet eej is an intense electric current flowing along the magnetic equator in the eregion of the ionosphere. The study of longitudinal and latitudinal variation of. A model equatorial electrojet sugiura 1966 journal. Equatorial electrojet as part of the global circuit.
Temporal and spatial power spectra from computer simulations of the equations modeling type ii irregularities in the equatorial electrojet are presented. Kobea et al equatorial electrojet as part of the global circuit. In the dayside ionosphere, the neutral winds set up a polarization electric field which usually points into the eastward direction. Wed like to understand how you use our websites in order to improve them. The equatorial electrojet eej is a narrow ribbon of current flowing eastward in the day time equatorial region of the earths ionosphere. The role of the equatorial electrojet on the distribution of. Equatorial electrojet an overview sciencedirect topics. In this paper we report on the fof2 variabilities for two equatorial regions ouagadougou. Equatorial electroject studies from ground and space. View the article pdf and any associated supplements and figures for a period of 48 hours. The electrojet current produces a large enhancement of the surface component of the. The abnormally large amplitude of variations in the horizontal components measured at equatorial. To study the electrojet, magnetically quiet days should be selected to ensure that the diurnal variation consists of the magnetic field variations due to the eej and. At the magnetic equator, where geomagnetic field lines are horizontal, a strong vertical polarization electric field can be established, which.
Download fulltext pdf download fulltext pdf the field of the equatorial electrojet from champ data article pdf available in annales geophysicae 242. Ionospheric eregion irregularities du1ing equatorial counter electrojet r g rastogi dcpartmclll of physics, gujarat university, ahmecabad 380 009. The equatorial electrojet eej is an intense electric current that flows in the ionosphere in a narrow zone above the magnetic dip equator during the daytime. Based on 10yr of magnetic field measurements by the champ satellite we draw a detailed picture of the equatorial electrojet eej tidal. Onwumwchili is an internationally known and highly respected expert in the equatorial electrojet field a brand of geomagnetism. The present study investigates the longitudinal variability of equatorial electrojet eej and counter electrojet cej phenomena using concurrent data from three equatorial and lowlatitude. Daytoday variability of equatorial electrojet and its role on. The equatorial anomaly in ionospheric total electron content and the equatorial electrojet current strength. Smes s, smus s, smls s, smed d, smud d, smld d sunlight and darkness electrojet indices.
An outstanding problem is the cause for the daytoday variability in the intensity of the electric. A comparison of equatorial electrojet in peru and east brazil. We describe here for the first time the morphology of the equatorial electrojet eej in the central american sector based on an analysis of the geomagnetic field components from six stations. Pdf equatorial electrojet as part of the global circuit. Numerical modeling of the equatorial electrojet ut. At the magnetic dip equator, where the magnetic field is exactly horizontal, this electric field has an interesting effect. Vhf communications via equatorial electrojet scattering. In addition, periodic variations that are in phase with the meridional eia movement are also revealed in the equatorial electrojet eej and f2 layer peak height hmf2 over chinese ionosonde stations. Electromagnetic induction by the equatorial electrojet.
1503 1575 541 1164 1538 896 1656 1489 310 822 950 1453 1153 1444 764 781 421 1138 146 1238 1617 1484 508 43 393 1238 1470 98 1436 19 1289 332 810