The topside sounder model tsm provides directly the scale height h t, while the incoherent scatter radar ionospheric model isrim provides electron density profiles and its scale height h r is determined by the lowest gradient in the topside part of the profile. Sar mode will make possible precise mapping of ionospheric irregularities. For this purpose topside sounder experiments have contributed by investigating the irregularities in the ionosphere as well as sounding the vertical structure of the ionosphere. Osherovich2, vladimir truhlik3, yongli wang4, dieter bilitza5, and shing f. Image is used to provide 2d mappings of the plasma. Topside sounding has proved valuable for revealing the structure of the high ionosphere and for investigating the resonance properties of a magnetoplasma. The topside ionosphere scale height extracted from two empirical models are compared in the paper. This package will provide primary standard measurements of electron density distributions in the topside ionosphere, where most of the ionization resides. While the bottomside ionosphere is easily accessible for groundbased observation, e. Using the topside sounding data by alouette and isis. The model was recently extended to include plasmasphere up to gps orbit heights kutiev et al. Based on these, we have concentrated on the design and development of a stateoftheart topside sounder and two radio beacons for deployment in a small, inexpensive satellite that can be quickly designed, constructed, and launched.
The topside ionosphere is a key region of the atmosphere since it contains plasma that. Variations of scale height at fregion peak based on ionosonde. Purchase the earths ionosphere, volume 96 2nd edition. Ionospheric specification with analytical profilers. The launch dates and orbit parameters are listed in table 1. Improvements of the international reference ionosphere model. Characterizing the topside bulge in the ionosphere of mars.
The ionosphere is somewhat of a battleground between the earths neutral atmosphere and the suns fully ionized atmosphere, in which the earth is embedded. Comparison of topside ionosphere scale height modeled by the. A novel strategy for topside ionosphere sounder based on spaceborne multipleinput multipleoutput mimo radar is proposed, which takes advantage of frequency division and code division fdcd as. A satellite based, sweptfrequency, hf topside sounder can do much. Marsis includes an active ionospheric sounding ais mode, which targets the topside ionosphere of mars. Highlatitude topside ionospheric vertical electron. In figure 4a, the noontime ratio between data and model is plotted for different modified. We are developing a new generation hf sounder that employs recent developments in technology. Fung1 1nasagoddard space flight center, geospace physics laboratory, code 673, heliophysics. Having ionospheric electron density distributions as a function of height, latitude, longitude, and time under different conditions is essential for scientific, technical, and operational purposes.
Radio sounding of the topside ionosphere has been a highly. First observations from the fixedfrequency topside sounder. A spaceborne frequency division radar scheme for topside. A satellite designed to measure ion concentration in the ionosphere from above the ionosphere explanation of topside sounder. Chapman model best described the topside ionosphere when compared to the topside sounder observations. The mars advanced radar for subsurface and ionospheric sounding marsis, aboard the esa spacecraft mars express, was deployed 17 june 2005 and commissioned in july 2005.
Comparison of topside ionosphere scale height modeled by the topside sounder model and incoherent scatter radar ionospheric model. The equatorial anomaly and the seasonal anomaly appear. The topside sounder will provide primary measurements of the electron density distributions through most of the ionosphere, throughout the world, and for various solar and geophysical conditions. Publications based on data from the alouette isis data restoration project. The satellites were placed in an 80 prograde, 3000kmapogee, 500kmperigee orbit. Introduction ionosphere is an essential constituent of earths space weather system, which has signi. Pdf model of topside ionosphere scale height based on. Pdf topside sounder model of scale height and transition. Introduction background topside ionosphere modelling dif. The epub format uses ebook readers, which have several ease of. A brief historical introduction is followed by such topics as radio techniques, plasma theory, oblique transmission, earthspace, amplitude, ionospheric disturbances, elf, vlf and lf, medium waves, hf and vhf. Modelling the topside ionosphere, the region above the height h mf 2 of the peak of ionosphere density n mf 2, poses particular di. Electron density profiles of the topside ionosphere.
Electron temperature models for the fregion topside ionosphere. The limits of our present knowledge of these rapidly developing subjects are discussed. This report gives some preliminary data from the magnetic. Evaluation of ionospheric profilers using topside sounding. Ionosphere topside sounder program electron density and geomagnetic field at alouette i orbit. Loworbiting observations at satellites with highaccuracy magnetometers onboard oersted, champ, st5 have provided the possibility to examine the ulf wave pc3, pi2, pc1 structure in the topside ionosphere. Unlike the bottomside ionosphere which has been well studied and modeled, topside ionosphere electron density profile measurements and models have remained a challenge. Development of satellite based sensor for improved. Abstract the martian ionosphere has for the first time been probed by a low frequency topside radio wave sounder experiment marsis gurnett et al. Electon density profiles of the topside ionosphere earthprints.
Upgrades to the topside sounders model assisted by digisonde tad and its validation at the topside ionosphere anna belehaki1, ioanna tsagouri1, ivan kutiev2, pencho marinov2, and stefka fidanova2 1 national observatory of athens, 15236 palaia penteli, greece. This elliptical orbit allows for a sampling of ion 63 density over multiple scale heights of the topside ionosphere. Observations of vertical reflections from the topside martian. An ionospheric topside sounder is a high frequency radar system that is located above the ionosphere, ideally onboard a polar orbiting satellite to provide global coverage.
The isis and alouette topside sounder satellites from the sixties to the eighties recorded millions of. Energetic ions can the second step in the creation of the ionosphere is the undergo a charge exchange process, cross magnetic field. The transient topside layer and associated current sheet in. A novel strategy for topside ionosphere sounder based on. Topside sounding of the earths ionosphere springerlink. In this paper, we focused on describing the response of the topside and bottomside ionosphere at low and middle latitudes to the october 2003 storms by combining ground. The topside sounder model tsm provides the topside ionosphere parameters as functions of day of the year, geomagnetic latitude, local time, solar flux at f10. Correction term for iri topside formula 10 bilitza 2004 evaluated the current iri topside model with the alouette 2, isis 1, and isis 2 topside sounder data that were mentioned in section 3. Part of the lecture notes in physics book series lnp, volume 687. The model provides the vertical scale height vsh as a function of month of the year, local time, geomagnetic latitude, solar flux f 107 and k p index. Depuev and pulinets 2004 developed a global empirical model of the topside electron density based on the data from intercosmos19 topside sounder.
Topside ionogram scaler with true height algorithm topist. Upgrades to the topside sounders model assisted by. Preliminary investigation of the structure of the upper. A new model of topside ionosphere scale height is developed, based on the vertical electron density ne profiles obtained from topside ionosondes. They proposed a convenient method to derive the topside ionospheric profile based on the chapman scale height, h m. Over the past few years, the satellite topside sounders have significantly contributed to the understanding of the upper ionosphere. This development was based on the topside sounders model. During phase i we have identified scientific, technical, and operational needs. The first topside ionospheric sounders 3, alouette and isis 4,5 recorded the amplitudes and echo delay times of ionospheric echoes as function of frequency in the same way it was done by the. Recently it was found that running a sounder in the ionosphere of the. Oyama2 1 department of applied mathematics, the university of sheeld, sheeld s3 7rh, uk. In the same way that an ionosonde measures the ionospheric profile from the ground, a topside sounder measures the ionospheric profile from a location above the fregion peak. The alouette, isis and intercosmos19 satellite missions provided large amounts of topside sounder data, but with limited coverage of relevant geophysical conditions e.
The alouette satellite carries an ionosonde well above this level and can make similar observations of the extended upper reaches of the ionosphere. The alouette and isis satellite missions provided large amount of topside sounder data over more. Model of topside ionosphere scale height based on topside sounder. It is found that ts and th have a dispersion of about 40% around the respective average, while the model reduces the dispersion model error to 27%. Some early results from the ionospheric topside sounder satellite. Alouette i the first topside sounder satellite was alouette i built in canada.
The time delay between transmission and reception is translated into effective ionospheric layer altitude. The most expensive part of these missions however is considered to be the. Between august 2005 and july 2007, the spacecraft performed approximately 2500 orbits. Iri topside modeling efforts and their current status. So much though that only a small percentage was analyzed during the mission life time. A novel strategy for topside ionosphere sounder based on spaceborne multipleinput multipleoutput mimo radar is proposed, which takes advantage of frequency division and code division fdcd as a substitution for sweptfrequency regime employed by the current ionosphere explorers, e. The isis and alouette topside sounder satellites from the sixties to the eighties recorded millions of ionograms but most were not analyzed in terms of electron. Empirical modeling of the topside ionosphere relies on the availability of good quality measured data that represent spatial and temporal variability with sufficient amount of data. Ts, th, and rt are now incorporated in a single model tsm topside sounder model. Oblique echoes from largescale horizontal gradients. Highlatitude topside ionospheric vertical electrondensity. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. Mathematical procedures and digital computer programs for converting observed topside curves into electron density profiles. New data on the topside electron density distribution.
Topside sounding is predicted to have a long and useful role in. Topside sounder model of scale height and transition height characteristics of the ionosphere. The topside scale height ts and transition height th models, previously developed by the authors, provided ts and th for any set of input parameters. This volume presents an uptodate survey of the theory and practice of radio wave propagation involving transmission through and reflection from the ionosphere. The explorer 31 satellite contains experiments designed to measure directly various properties of the earths ionosphere. The earths ionosphere is a magnetoionic medium imbedded in a background.
Therefore the sounder observations of the topside densities and their. Model of topside ionosphere scale height based on topside. The martian ionosphere has for the first time been probed by a low frequency topside radio wave sounder experiment marsis gurnett et al. Ionosphere sounding is significant for space science research and compensation of ionospheric effects on space information systems. Although the densities are low compared to the f layer peak, the path length is long, and as indicated above, the topside and plasmaspheric densities are not well known.
Publications based on data from the alouetteisis data restoration project. Highlatitude topside ionospheric vertical electrondensityprofile changes in response to large magnetic storms robert f. The alouette and isis topside sounder satellites recorded a great wealth of information about the topside ionosphere during their long period of operations from 1962 to 1990. The present paper describes the summary of the results of the sounder experiment, that were made in the topside ionosphere. Except for the electron density for which a wealth of data is available, the scarcity of relevant measurements. The satellite has yielded new information on the arrangement of irregularities in sheets and the structure of plasma resonances in the ionosphere. In that case, the aimi panel suggests that the dynamic dynamical neutral atmosphereionosphere coupling mission be put forth as the decadal surveys numberone priority for the 202022 decade. The density profiles in the martian ionosphere have for the first time been observed for solar zenith angles less than 48 degrees. Pdf a new model of topside ionosphere scale height is developed, based on the vertical electron density ne profiles obtained from topside. The transient topside layer and associated current sheet in the ionosphere of mars andrew j.
Plasma physics and electrodynamics emphasizes the study of plasma physics and electrodynamics of the ionosphere, including many aeronomical influences. These interplanetary spacecraft carried receivers for the 423. The intercosmos19 scientific equipment included the topside sounder is338. Echo sounding of the ionosphere from below has, for four decades, been a fruitful way of obtaining information about the upper atmosphere and the effects o. The tis will address the need for increased space situational awareness and environmental monitoring by estimating electron density profiles in the topside of the ionosphere. The existing uncertainties about the electron density profiles in the topside ionosphere, i. A great quantity of radio echo data has been accumulated, from which the ionospheric electrondensity distribution can be determined. Ionospheric physics of photoionization is given by hudson 1971 and stolarski are important to the dynamics of the ionosphere, especially and johnson 1972. One major challenge for topside nh modeling is finding a suitable mathematical representation of the profiles e. The topside ionosphere is the region above f2 layer in ionosphere, and the topside ionosphere exploration is. In telecommunication and radio science, an ionospheric sounding is a technique that provides realtime data on highfrequency ionosphericdependent radio propagation, using a basic system consisting of a synchronized transmitter and receiver.
Topside sounder article about topside sounder by the. Students of aeronomy and radio wave propogation are introduced to basic wave theory in absorbing, anisotropic and dispersive media, and to the physics of. Response of the topside and bottomside ionosphere at low. Characterizing the topside bulge in the ionosphere of mars table of contents cover page table of contents.
Topside sounder model of scale height and transition. Ionospheric radio replaces an earlier publication ionospheric propogation and is aimed at professional scientists, engineers, and students who need an intermediatelevel reference andor text. Radio scientists, including those in the isis program, have long envisioned extension of sounding to altitudes well beyond 3000 km altitude, the approximate. Groundbased ionosondes are widely used to probe the part of the ionosphere lying below the level of maximum electron density at about 300 km. The previous eight satellite sounders have measured the critical frequency of the f2 ionosphere region using traditional swept frequency methods. Usage of isis topside sounder electron density profiles. The details of the sounder work can be found in the book. Five different localized phenomena have been observed in the ionosphere by the topside sounder, and three of these are shown to occur at the latitudes at which the magnetic field lines which pass through the hearts of the three radiation belts enter the earths atmosphere. The aim of this research is the determination of the structure and variation of the topside ionosphere at midlatitudes during the sunrise period, based on electrondensity measurements obtained with the aid of alouette i, the canadian topside sounder satellite. The design of sweptfrequency topside sounders ieee journals.
Yearly variations in the lowlatitude topside ionosphere g. Ionospheric sounding from ground ionosonde and topside sounder showing method of. Klenzing et al topside equatorial ionospheric density x 5 62 near 400 km and apogee near 860 km. Linear varychap topside electron density model with. Observations of polar cusp and polar cap ionospheric.
Students of aeronomy and radio wave propogation are introduced to basic wave theory in absorbing, anisotropic and dispersive media, and to the physics of production, loss and movement of plasma in the. Successful empirical modeling of the topside ionosphere relies on the availability of good quality measured data. Yearly variations in the lowlatitude topside ionosphere. Results of the plasma wave sounder experiments on board. Halekas1 1department of physics and astronomy, the university of iowa, iowa city, ia 2solar system exploration division, nasa goddard space flight center, greenbelt, md. Electron density profiles in the ionosphere and exosphere, proceedings of the nato advanced study institute held at skeikampen, norway, april, 1961. The ionospheric topside electron density profile can be obtained from topside sounder measurements or by. Comparison of topside ionosphere scale height modeled by. Model of topside ionosphere scale height based on topside sounder data article pdf available in advances in space research 375. A satellitebased, sweptfrequency, hf sounder can obtain electron density profiles on a global scale.
Alouette i topside sounder satellite on the 75th meridian from heights of 400 km to km. Topside ionosphere scale height how is topside ionosphere. The linear varychap function has received increased attention in describing the topside ionosphere due to its good performance for predicting and extrapolating radiooccultation ro electron density ionospheric profiles. Solar control of the martian ionosphere as detected by.
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