This report gives some preliminary data from the magnetic. A novel strategy for topside ionosphere sounder based on spaceborne multipleinput multipleoutput mimo radar is proposed, which takes advantage of. Read retrieval of in situ electron density in the topside ionosphere from cosmic radio noise intensity by an artificial neural network, radio science on deepdyve, the largest online rental service for scholarly research with thousands. Over the past few years, the satellite topside sounders have significantly contributed to the understanding of the upper ionosphere.
Statistical analysis of the ionization ledge in the. The topside sounders could provide pertinent information over most of the ionosphere i. Retrieval of in situ electron density in the topside. The topside tec was comparable to the total tec in the storm period, and a significant enhancement of tec occurred in the topside ionosphere. Radio sounding of the topside ionosphere has been a highly successful means of investigating the physics of the ionosphere and of the innermost plasmasphere e. Studies of the geographical distributions of the different kinds of spread f, sporadic e, and other phenomena will be facilitated by the satellite. During a particular stage in the development of the anomaly, a ledge of ionization exists above the peak of the flayer. Topside sounding of the earths ionosphere springerlink. The ionosphere is somewhat of a battleground between the earths neutral atmosphere and the suns fully ionized atmosphere, in which the earth is embedded. A satellitebased, sweptfrequency, hf sounder can obtain electron density profiles on a global scale. More phenomena will undoubtedly be recognized as the records are studied. The previous eight satellite sounders have measured the critical frequency of the f2 ionosphere region using traditional swept frequency methods. Improvements of the international reference ionosphere model. 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.
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 the time delay between transmission and reception is translated into effective ionospheric layer altitude. Yearly variations in the lowlatitude topside ionosphere. 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. Model of topside ionosphere scale height based on topside sounder. The alouette, isis and intercosmos19 satellite missions provided large amounts of topside sounder data, but with limited coverage of relevant geophysical conditions e. The sounder spectrograms typically have a single trace of echoes, which are controlled by reflections from the. Pdf model of topside ionosphere scale height based on. The cosmos1809 sounder worked from january 15, 1 987 to may 22, 1993. A satellite designed to measure ion concentration in the ionosphere from above the ionosphere explanation of topside sounder. It is shown that the model values capture well the data variations. Low latitude topside ionospheric response to magnetic storms from. Ionospheric sounding from ground ionosonde and topside sounder showing method of. Some early results from the ionospheric topside sounder. Expanding the topside sounder digital data collection.
Students of aeronomy and radio wave propogation are introduced to basic wave theory in absorbing, anisotropic and dispersive media, and to the physics of. Upgrades to the topside sounders model assisted by. The evolution of the sweptfrequency sounders is traced from the first sounder, flown in the alouette i satellite, to the more sophisticated ones in alouette ii and isisi, and engineering problems of particular interest or difficulty are. The ionospheric topside electron density profile can be obtained from topside sounder measurements or by theorematic models. 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. No significant enhancement of tec occurred in the topside ionosphere at these latitudes. Radio scientists, including those in the isis program, have long envisioned extension of sounding to altitudes well beyond 3000 km altitude, the approximate. 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. About cookies, including instructions on how to turn off cookies if you wish to do so. Alouette i the first topside sounder satellite was alouette i built in canada. A spaceborne frequency division fd radar scheme for topside ionosphere. The density profiles in the martian ionosphere have for the first time been observed for solar zenith angles less than 48 degrees. Alternatively, the ionospheric data from one such topside sounder and from other sources could assimilate into a new generation of physical models. Usage of isis topside sounder electron density profiles.
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 corresponding author. First observations from the fixedfrequency topside sounder. 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. The design of sweptfrequency topside sounders ieee. Ionospheric predictions and information will also help gps users, radio users, satellite users, and electric utilities. Satellite topside sounder and in situ instruments, on the other hand, provide global coverage but only during the lifetime of the satellite.
Recently, an empirical model of the topside ionosphere scale height was developed, based on the vertical electron density profiles from the topside sounders onboard alouette and isis satellites. In 1958, sputnik3 carried an ion spectrometer which provided a limited study of the heavier ions, above 10 amu, which were observed. Ionosphere sounding is significant for space science research and compensation of ionospheric effects on space information systems. Comparison of topside ionosphere scale height modeled by the. New data on the topside electron density distribution. Large n e h changes were observed during the storms in all cases.
Response of the topside and bottomside ionosphere at low. Purchase the earths ionosphere, volume 96 2nd edition. Observations of vertical reflections from the topside martian. By continuing to browse this site you agree to us using cookies as described in about cookies remove maintenance message. These interplanetary spacecraft carried receivers for the 423. Highlatitude topside ionospheric vertical electrondensity. A satellite based, sweptfrequency, hf topside sounder can do much. The database allows you to get topside electron density profiles for chosen time periods within these intervals. Sounding of the topside ionosphereplasmasphere based on. Comparison of topside ionosphere scale height modeled by the topside sounder model and incoherent scatter radar ionospheric model. Topside modeling activities have relied heavily on measurements from the very first topside sounder satellite, alouette 1.
Groundbased ionosondes are widely used to probe the part of the ionosphere lying below the level of maximum electron density at about 300 km. Except for the electron density for which a wealth of data is available, the scarcity of relevant measurements. Depuev and pulinets 2004 developed a global empirical model of the topside electron density based on the data from intercosmos19 topside sounder. Observations of vertical reflections from the topside.
We are developing a new generation hf sounder that employs recent developments in. The most expensive part of these missions however is. The intercosmos19 sounder worked from march 5, 1979 to april 8, 1982. The earths ionosphere is a magnetoionic medium imbedded in a background.
The seasonal behaviour of the topside ionosphere nasaads. 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. Introduction background topside ionosphere modelling dif. The transient topside layer and associated current sheet in the ionosphere of mars andrew j. Mathematical procedures and digital computer programs for converting observed topside curves into electron density profiles. When one spacecraft is at higher altitude, it measures electromagnetic and precipitating particle energy inputs and properties of outflowing ions, while the magnetically aligned lowaltitude spacecraft measures the properties of the ion and neutral gas. Pdf a new model of topside ionosphere scale height is developed, based on the vertical electron density ne profiles obtained from topside. Low latitude topside ionospheric response to magnetic storms. The aim of this paper is to compare the scale height determined by the topside sounders model and bottomside digisonde profiles extrapolated above 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 substitution for sweptfrequency regime employed by the current ionosphere explorers, e. The limits of our present knowledge of these rapidly developing subjects are discussed. The topside ionosphere scale height extracted from two empirical models are compared in the paper. Topside sounding is predicted to have a long and useful role in. 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.
The existing uncertainties about the electron density profiles in the topside ionosphere, i. The topside ionosphere of mars is known to show variability and transient topside layers. Topside sounder model of scale height and transition height characteristics of the ionosphere. You may submit questions of a technical nature to developers. In this study, we analyzed the electron density profiles measured by the radio occultation technique aboard the mars global surveyor spacecraft to study the topside ionosphere of mars. Successful empirical modeling of the topside ionosphere relies on the availability of good quality measured data. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. Tsm output parameters are used to formulate a concept of a new profiler, named topside ionosphere and plasmasphere profiler tipp, as a tool for obtaining the vertical ne distribution in the upper ionosphere and plasmasphere when nmf2 and hmf2 are specified. In the present paper the results of an investigation of the effects of magnetic declination and solar control on the topside electron density distribution are presented and are examined in the light of a. The isis and alouette topside sounder satellites from the sixties to the eighties recorded millions of. Topside sounding has proved valuable for revealing the structure of the high ionosphere and for investigating the resonance properties of a magnetoplasma.
Using the topside sounding data by alouette and isis. Alouette topside sounder data acquired over north america during the solstice periods of 1962 and 1963 indicate that, over a wide range of middle latitudes, the midday electron concentration values at various fixed heights 400, 600, 800 and km are always substantially greater, by a factor of about two, at midsummer than at midwinter. Benson3 1space environment corporation 221 gateway drive, suite a providence, ut 84332 usa 2natural resources canada. It plays an important role in atmospheric electricity and forms the. Topside sounder model of scale height and transition. The ionosphere ansfr is the ionized part of earths upper atmosphere, from about 60 km 37 mi to 1,000 km 620 mi altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. A novel strategy for topside ionosphere sounder based on. Ionospheric physics of photoionization is given by hudson 1971 and stolarski are important to the dynamics of the ionosphere, especially and johnson 1972. Near the equator, the topside tec tended to be comparable to the bottomside tec in the main phases of the storms. Pdf topside sounder model of scale height and transition.
Topside ionosphere scale height how is topside ionosphere. In the present study, a 12month period of electron density and electron temperature data observed by the hinotori satellite is analysed to investigate the yearly variations of the topside. Publications based on data from the alouetteisis data restoration project. The martian ionosphere has for the first time been probed by a low frequency topside radio wave sounder experiment marsis gurnett et al. The proposed new generation topside sounder will provide the electron density distribution between the f layer peak and the lower plasmasphere, over much of the.
Evaluation of ionospheric profilers using topside sounding data article in radio science 493. The satellite has yielded new information on the arrangement of irregularities in sheets and the structure of plasma resonances in the ionosphere. Automated processing of isis topside ionograms dieter bilitza,1 xueqin huang,2 bodo w. Abstract for the purpose of clarifying the occurrence character of the ionization ledge and its relation to the diurnal variation of the eastward electric field, plasma density profiles in the equatorial ionosphere of the american longitude sector obtained from topside sounder onboard the ohzora exosc and the isis2 satellites were analyzed. Ionospheric radio replaces an earlier publication ionospheric propogation and is aimed at professional scientists, engineers, and students who need an intermediatelevel reference andor text. Model of topside ionosphere scale height based on topside sounder data article pdf available in advances in space research 375. 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. The alouette satellite carries an ionosonde well above this level and can make similar observations of the extended upper reaches of the ionosphere. An initial feasibility study was performed by calvert et al. Energetic ions can the second step in the creation of the ionosphere is the undergo a charge exchange process, cross magnetic field.
Electron temperature models for the fregion topside ionosphere. One of the challenges of ionosphere research is to know enough about these two vast fields of research to make sense out of ionospheric phenomena. Publications based on data from the alouette isis data restoration project. Observations of polar cusp and polar cap ionospheric. A great quantity of radio echo data has been accumulated, from which the ionospheric electrondensity distribution can be determined. The sounder spectrograms typically have a single trace of echoes, which are. Electron density profiles in the ionosphere and exosphere, proceedings of the nato advanced study institute held at skeikampen, norway, april, 1961. Comparison of topside ionosphere scale height modeled by.
The study of the equatorial ionosphere, by means of topside sounder ionograms. Li school of electronics and information engineering, beihang university, beijing 100191, china abstracta novel strategy for topside ionosphere sounder based on spaceborne multipleinput multipleoutput mimo radar is. This volume presents an uptodate survey of the theory and practice of radio wave propagation involving transmission through and reflection from the ionosphere. A spaceborne frequency division fd radar scheme for topside ionosphere sounding is proposed to decrease the sweptfrequency period of traditional radar. The satellites were placed in an 80 prograde, 3000kmapogee, 500kmperigee orbit. Topside ionogram scaler with true height algorithm topist.
Topside sounder article about topside sounder by the. Radio sounding of the topside ionosphere has been a highly. Dec 19, 2006 the martian ionosphere has for the first time been probed by a low frequency topside radio wave sounder experiment marsis gurnett et al. Anomalous heating of the topside ambient subauroral electrons during stormtime con ditions is thought to be a consequence of a downward heat.
The explorer 31 satellite contains experiments designed to measure directly various properties of the earths ionosphere. The ionospheric topside sounder measurement database developed at the us national space science data center nssdc is a valu able source of information when investigating the composition and complex dynamics of the upper ionosphere. Topside sounder observations of the equatorial anomaly in. Variations of scale height at fregion peak based on ionosonde measurements during solar maximum over the crest of equatorial ionization anomaly region. 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. Electon density profiles of the topside ionosphere earthprints. Evaluation of ionospheric profilers using topside sounding. The present paper describes the summary of the results of the sounder experiment, that were made in the topside ionosphere and plasmasphere. This instrument was designed to operate between 3 khz and 3 mhz so as to sound the full range of electron densities expected to exist between the earths magnetosheath and topside ionosphere. Abstracta 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. Halekas1 1department of physics and astronomy, the university of iowa, iowa city, ia 2solar system exploration division, nasa goddard space flight center, greenbelt, md. Ionosphere topside sounder program electron density and geomagnetic field at alouette i orbit. During the last 40 years or so a number of satellites have been launched to measure various characteristics of the.