An investigation of the ionospheric f

Ngwira and L.

Investigation of Ionospheric Variations During Magnetic Storm Over Turkey

Mckinnell and P. Cilliers and E. The effects of the 15 May severe geomagnetic storm on the South African iono-sphere are studied using ground-based and satellite observations. Ionospheric disturbances have less frequently been investigated over mid-latitude regions. Recently, a number of studies investigated their evolution and generation over these regions.

This paper reports on the first investigation of travelling ionospheric disturbances TIDs over mid-latitude South Africa. In addition, the F-region critical frequency foF2 values observed at two ionosonde stations show that the ionospheric response as seen by ionosondes was different from that of the TEC response during the disturbance period.

The dissimilarity between the TEC and the foF2 suggests that two competing drivers ex. Documents: Advanced Search Include Citations. NgwiraL. MckinnellP. CilliersE. Abstract The effects of the 15 May severe geomagnetic storm on the South African iono-sphere are studied using ground-based and satellite observations.

Powered by:.Variations in solar, geomagnetic, and seismic activity cause disturbance in the ionosphere that can be monitored effectively using GPS observations. Total electron content TEC is an effective parameter to understand structure of ionosphere and investigate ionospheric variability by making use of GPS receivers.

After that, 27 quiet days were defined to detect ionospheric disturbance during storm. Using statistical method, averages of TEC values were computed to obtain upper and lower bounds. This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. Adekoya, B. Space Sci. Astafyeva, E. Balan, N. Blagoveshchenskii, D. A review, Geomagn. Cherniak, I.

Ciraolo, L. Contadakis, M. Italy, vol. Google Scholar. Dabas, S. Dashora, N. Space Res. Fagundes, P. Fejer, B. Joshua, B. Paul, A. Rao, P. Sharma, S. Thomas, E. Classification of Kp index values.

Accessed March 18, Vijaya Lekshmi, D. Zhao, B. Zhong, J. Download references. Correspondence to Samed Inyurt. Reprints and Permissions.

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Download citation. Received : 28 May Revised : 16 August Accepted : 26 September Published : 03 April Space Sci. This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. Aggson, N. Maynard, F. Herrero, H.

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Mayr, L. Brace, M. Liebrecht, Geomagnetic equatorial anomaly in zonal plasma flow. Akasofu, R. Dewitt, Dynamo action in the ionosphere and motions of the magnetospheric plasma.

an investigation of the ionospheric f

Alken, S. Maus, A.

an investigation of the ionospheric f

Richmond, A. Maute, The ionospheric gravity and diamagnetic current systems. Alken, A. Maute, Ionospheric gravity and pressure gradient current. Anderson, H. Korth, C. Waters, D.To browse Academia. Skip to main content. Log In Sign Up. Download Free PDF. Muzammil Mushtaq Hussain. Syed Nazeer Alam. Faisal Afridi. Primarily, univariate analysis has been done, which shows the variations in f0F2 at different local times, seasons and in the range of sunspot numbers SSNin which winter and semi-annual anomalies are detected in the months of December and March respectively.

Secondly, the regression analysis is being used as a bivariate data analysis. The results proved a significantly nonlinear relationship exists between f0F2 and SSN.

In both solar cycles, saturation effects are seen in the month of March during the noontime period and immensely in June during the midnight time. The behavior of the ionosphere has been studied for different latitudes, seasonal effects and sunspot dynamic conditions, in which this paper plays an essential role in it.

The solar activity reliance on the components coexist with ionized particles and it is F2 layer's critical frequency of the Ionosphere f0F2 or called the Ionosphere. This region has been affected peak electron density NmF2 have been considered by the intense solar natural radiation, such as Extreme for a long time [].

Due to fluctuation linear by earlier works. A nonlinear dependence of the in the ionosphere constituents i. Then further investigations portion of the atmosphere into four layers such as D, E, confirmed that the solar activity has an effect on the F1 and F2. The F2 layer is a prominent one because it ionosphere which can be well represented by a persists all the time in any kind of solar or terrestrial quadratic pattern [13].

A higher-order polynomial does conditions and responsible for long haul not effectively improve the fitting among solar activity communication [1]. It is our motive to study ionospheric and ionospheric parameters [14]. But it is not always possible In our univariate analysis, we used some descriptive to direct measured EUV radiations coming from the statistics and the graphical techniques such that the Sun, that is the main source of ionization in the region histogram and box plots were analyzed on the of the ionosphere.

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So researchers have to depend on parameter of monthly median hourly f0F2 values. The solar proxies, in this scenario the Sun's most evident bivariate data were also analyzed by using the temporary features, i.

In this paper, primarily, we show the effect also the other advantages of sunspot numbers are the of the different range of sunspot numbers on the longest available data and easy to measure.

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Finally, analyzed the effect of the sunspot numbers on the noon and midnight values of f0F2 in the months of March, June, September and December.Metrics details.

Low Earth orbiting geomagnetic satellite missions, such as the Swarm satellite mission, are the only means to monitor and investigate ionospheric currents on a global scale and to make in situ measurements of F region currents. High-precision geomagnetic satellite missions are also able to detect ionospheric currents during quiet-time geomagnetic conditions that only have few nanotesla amplitudes in the magnetic field.

An efficient method to isolate the ionospheric signals from satellite magnetic field measurements has been the use of residuals between the observations and predictions from empirical geomagnetic models for other geomagnetic sources, such as the core and lithospheric field or signals from the quiet-time magnetospheric currents. This study aims at highlighting the importance of high-resolution magnetic field models that are able to predict the lithospheric field and that consider the quiet-time magnetosphere for reliably isolating signatures from ionospheric currents during geomagnetically quiet times.

The effects on the detection of ionospheric currents arising from neglecting the lithospheric and magnetospheric sources are discussed on the example of four Swarm orbits during very quiet times. The respective orbits show a broad range of typical scenarios, such as strong and weak ionospheric signal during day- and nighttime, respectively superimposed over strong and weak lithospheric signals.

Measurements of the geomagnetic field are an effective and often the only means to characterize these processes and their temporal changes. The separation of the overall observation into the contributions from the various sources is a major challenge. This study aims to discuss the separation of the ionospheric signal by predicting other sources with the use of modern geomagnetic models.

In contrast, ionospheric currents, e. Low-amplitude currents are always present, independently from the geomagnetic activity level. Ionospheric currents during quiet times constitute a substantial part of the geomagnetic background and are important effects that also have to be dealt with when we want to improve geomagnetic models.

A very efficient approach to studying these currents is to analyze the difference between observations and predictions of effects from non-ionospheric sources derived from geomagnetic field modeling.

Additionally, high-resolution empirical models exist that have the capability to predict also the lithospheric field and the quiet-time magnetospheric field dominated by the magnetospheric ring current. Updates have recently been published by Finlay et al. The CHAOS-5 model used for this study provides predictions up to a spherical harmonic degree ofcorresponding to about km spatial resolution.

This paper does not aim at discussing the role of high-resolution lithospheric field models for regional and global geological investigations, but it highlights their relevance for reliably monitoring ionospheric currents at satellite altitudes. An overlap in magnitude and scale length of the different geomagnetic sources has been demonstrated from global analyses, e.

Here, we want to demonstrate the importance of the application of high-resolution lithospheric and magnetospheric field models for separating and analyzing the ionospheric field. We do this firstly by reviewing recent progress in this field and secondly by highlighting relevant effects with the help of selected orbits of Swarm, representative for magnetically quiet times.

For scientific studies based on residuals between satellite observations and high-resolution geomagnetic field models see, e. Here, we want to provide a short review on publications that are more recent as well as those that have focused on ionospheric currents and that will be relevant later in this study, i. Such quiet-time ionospheric currents show typical spatial and temporal characteristics. Here, observations have been reduced by core field predictions and by a homogenous magnetospheric field model based on the Dst index.

These authors derived a correlation of 0. Similar good correlations were derived between interplanetary magnetic field proxies and the total field residuals.

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However, for very quiet conditions and the dark polar hemisphere these correlations are considerably reduced, and variations in the solar wind could not be related to variations in the polar ionospheric currents.

During geomagnetic quiet times, the authors also identified stationary anomalies and attributed those to the lithospheric field, which was not accounted when building the magnetic residuals.

A climatology of the dayside, midlatitude Sq current system based on spherical harmonic analysis has been derived from CHAMP data by Pedatella et al. The authors reduced the observations by the core field and the magnetospheric field and further minimized the effect from radial currents and induction in the solid Earth. The global approach that is possible from satellite data allowed to additionally investigate longitudinal variations of Sq, and they attributed the longitudinal structure to the orientation and strength of the geomagnetic background field and to tidal winds.

A global empirical model for the dayside equatorial electrojet EEJ has been derived from the CHAMP mission by Alken and Maus based on total field residuals to core, lithosphere and magnetosphere models. From this global analysis, they found that the influence of the diurnal eastward-propagating mode with wavenumber-3, DE3, is particularly strong in determining the longitudinal structure of its amplitude, e.

This feature was also observed for other parameters in the low-latitude upper atmosphere see for a review, e.

Values for EEJ and the eastward electric field are now regularly derived from Swarm observations for each dayside orbit Alken et al. From the Swarm constellation, the authors found that the longitudinal gradient for the dayside electric field varies with longitude and amounts up to 0.

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High-precision magnetic satellite observations enabled the observation of F region ionospheric currents at low- and midlatitudes, which are not clearly detectable on ground since they are masked by E region currents during day or because their signals during nighttime are too weak to be detected at such far distance see Olsen and Stolle Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer.

In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. A connection between thunderstorms and the ionosphere has been hypothesized since the mids 1. Several mechanisms have been proposed to explain this connection 234567and evidence from modelling 8 as well as various types of measurements 91011121314 demonstrate that lightning can interact with the lower ionosphere. Here we identify a statistically significant intensification and descent in altitude of the mid-latitude sporadic E layer directly above thunderstorms.

Because no ionospheric response to low-pressure systems without lightning is detected, we conclude that this localized intensification of the sporadic E layer can be attributed to lightning.

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We suggest that the co-location of lightning and ionospheric enhancement can be explained by either vertically propagating gravity waves that transfer energy from the site of lightning into the ionosphere, or vertical electrical discharge, or by a combination of these two mechanisms.

Wilson, C. The electric field of a thundercloud and some of its effects. Bauer, S.

an investigation of the ionospheric f

A possible troposphere-ionosphere relationship. Bhar, J. Effect of thunderstorms and magnetic storms on the ionisation of the Kennelley-Heaviside Layer. Mitra, S. Thunderstorms and sporadic E ionisation of the ionosphere. Nature— Rastogi, R.

Thunderstorms and sporadic E layer ionisation. Indian J.

an investigation of the ionospheric f

Google Scholar. Ross, W.The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth.

As early asthe German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12,in St. John's, Newfoundland now in Canada using a The message received was three dits, the Morse code for the letter S. To reach Newfoundland the signal would have to bounce off the ionosphere twice.

Jack Belrose has contested this, however, based on theoretical and experimental work.

Lightning-induced intensification of the ionospheric sporadic E layer

InOliver Heaviside proposed the existence of the Kennelly—Heaviside layer of the ionosphere which bears his name. Heaviside's proposal included means by which radio signals are transmitted around the Earth's curvature.

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Heaviside's proposal, coupled with Planck's law of black-body radiation, may have hampered the growth of radio astronomy for the detection of electromagnetic waves from celestial bodies until and the development of high-frequency radio transceivers [ citation needed ]. Also inArthur Edwin Kennelly discovered some of the ionosphere's radio-electrical properties. Inthe U. Congress imposed the Radio Act of on amateur radio operatorslimiting their operations to frequencies above 1. The government thought those frequencies were useless [ citation needed ].

This led to the discovery of HF radio propagation via the ionosphere in InScottish physicist Robert Watson-Watt introduced the term ionosphere in a letter published only in in Nature :. We have in quite recent years seen the universal adoption of the term 'stratosphere'. The term 'ionosphere', for the region in which the main characteristic is large scale ionisation with considerable mean free paths, appears appropriate as an addition to this series.

In the early s, test transmissions of Radio Luxembourg inadvertently provided evidence of the first radio modification of the ionosphere; HAARP ran a series of experiments in using the eponymous Luxembourg Effect.

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