DOCSLIB.ORG

Comparison of Superdarn Peak Electron Density Estimates Based on Elevation Angle Measurements to Ionosonde and Incoherent Scatter Radar Measurements Alexander V

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Comparison of Superdarn Peak Electron Density Estimates Based on Elevation Angle Measurements to Ionosonde and Incoherent Scatter Radar Measurements Alexander V Koustov et al. Earth, Planets and Space (2020) 72:43 https://doi.org/10.1186/s40623-020-01170-w FULL PAPER Open Access Comparison of SuperDARN peak electron density estimates based on elevation angle measurements to ionosonde and incoherent scatter radar measurements Alexander V. Koustov1* , Sydney Ullrich1, Pavlo V. Ponomarenko1, Robert G. Gillies2, David R. Themens3 and Nozomu Nishitani4 Abstract Measurements of the electron density at the F region peak by the Canadian Advanced Digital Ionosonde (CADI) and the Resolute Incoherent Scatter Radar (RISR) are used to assess the quality of peak electron density estimates made from elevation angle measurements by the Super Dual Auroral Radar Network (SuperDARN) high-frequency radar at Rankin Inlet (RKN). All three instruments monitor the ionosphere near Resolute Bay. The CADI-RKN joint dataset comprises measurements between 2008 and 2017 while RISR-RKN dataset covers about 60 daylong events in 2016. Reasonable agreement between the RKN estimates and measurements by CADI and RISR is shown. Two minor dis- crepancies are discussed: RKN radar daytime peak electron density overestimation by ~ 10% and underestimation by up to 30% in other time sectors. In winter nighttime and dawn, cases were identifed in which the RKN radar signif- cantly overestimates the peak electron density. This occurs when the phase in the RKN interferometer measurements is incorrectly shifted by 2π , and this is most signifcant when electron densities are low. Statistical ftting to the joint data sets, split into four time sectors of a day, has been done and parameters of the ft have been determined. These allow slight adjustment of measured real-time RKN values to better refect real peak electron densities in the iono- sphere within its feld of view. Keywords: F region electron density, SuperDARN radars, Elevation angles, CADI ionosonde, RISR incoherent scatter radar Introduction radio waves toward the ground where they can be either Knowledge of the electron density distribution in the detected by a communication receiver or can be back- high-latitude ionosphere is fundamentally important for scattered by the surface and detected by a ground-based various practical applications such as high-frequency radar receiver near their location of transmission. (HF) radio wave communication (Davies 1990; Hun- Decades of research has led to a general understanding sucker 1991; Rawer 2013). At HF, radio waves expe- of the horizontal and vertical distributions of the electron rience signifcant ionospheric refraction resulting in density in the ionosphere, culminating in the develop- strong bending of radio paths and occasionally turning ment of empirical models of the ionosphere such as the International Reference Ionosphere (IRI, Bilitza et al. 2017) and the Empirical Canadian High Arctic Iono- *Correspondence: [email protected] spheric Model (E-CHAIM, Temens et al. 2017, 2019), 1 Department of Physics and Engineering Physics, University which is an improved empirical model for high-latitude of Saskatchewan, Saskatoon, SK, Canada Full list of author information is available at the end of the article regions. © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creat iveco mmons .org/licen ses/by/4.0/. Koustov et al. Earth, Planets and Space (2020) 72:43 Page 2 of 14 It is well established that the ionospheric F region has the estimates rely on the occurrence of Pedersen rays the largest electron density and thus afects HF radio (Davies 1990) that reach the top of the ionospheric layer waves in the most signifcant way. Te electron density and return with about the same elevation angle from a at the F layer maximum NmF2 has always been of spe- number of ranges (Ponomarenko et al. 2011). Te algo- cial interest, both experimentally and in the theoretical rithm by Ponomarenko et al. (2011) requires an echoing modeling of the physical processes leading to ionosphere region with Pedersen rays extending at least ~ 200 km. formation (e.g., Kutiev et al. 2013). Despite signifcant Although the possibility of producing peak electron progress in this area, numerous details and trends in the density measurements with the SuperDARN radars has electron density distribution require further investigation been known for years, the method has not been regularly so that forecasting capabilities can be improved. implemented and very limited testing of the method has Te electron density at the F region peak has been been done so far (André et al. 1998; Ponomarenko et al. traditionally studied through ionosonde observations 2011). Part of the problem is the need for reliable echo (Davies 1990; Hunsucker 1991; Rawer 2013). Tis is elevation angle measurements which require difcult because obtaining the maximum electron density value calibration of phased arrays in the HF band (e.g., Pon- from routinely recorded ionograms is a relatively easy omarenko et al. 2015, 2018). Testing has also been limited task provided that the ionogram traces are well defned. by the need for an independent instrument measuring Ionosonde data are usually available with 1 to 15 min res- the electron density distribution in the ionosphere within olution. Over the years, a signifcant body of data, cover- the radar feld of view. Very few SuperDARN radars have ing a wide range of latitudes, has been accumulated (e.g., ionosondes or ISRs positioned at ranges where electron https ://www.sws.bom.gov.au/World _Data_Centr e). densities are typically obtained. Te electron density distribution with height, along Te SuperDARN radar at Rankin Inlet (RKN) is one with the F layer peak values, is also routinely retrieved of a few radars that has reliable elevation angle data for from incoherent scatter radar (ISR) measurements (Bey- many years of operation (Chisham 2018; Ponomarenko non and Williams 1978; Hunsucker 1991; Rawer 2013). et al. 2011). Continuous operation of the Canadian Modern phased-array ISRs sound the ionosphere along Advanced Digital Ionosonde (CADI) at Resolute Bay several beams nearly simultaneously, allowing them (Jayachandran et al. 2009) and the recent deployment of to build a 3-D distribution of the electron density with an ISR at the same location (to be referred to as RISR) temporal resolutions often as good as 1 min (e.g., Gil- provide an excellent opportunity for testing the quality of lies et al. 2016). One important aspect of both ionosonde electron density estimates from RKN observations near and ISR operations is that the region of measurements the Resolute Bay zenith. is reasonably constrained and known. Tis is necessary Tis study expands the initial work by Ponomarenko for multi-instrument studies, and for the development et al. (2011) by performing a multi-year and two-instru- of ionospheric models, such as the IRI series (Bilitza ment comparison of the F region peak electron density 2018), E-CHAIM and others (e.g., Temens et al. 2017, estimates from RKN observations of ionospheric echoes. 2019). However, for some applications a global coverage is highly desired. Despite the continuously growing array SuperDARN method of F region peak electron of ionosondes and ISRs, their numbers are still limited density estimates from elevation angle and achieving global coverage for instantaneous electron measurements density measurements is still a challenging task. SuperDARN HF radar waves transmitted into the iono- Relatively recently, the Super Dual Auroral Radar Net- sphere experience strong refraction that depends on the work (SuperDARN) radars, which operate within the HF vertical distribution of the electron density. An important band, have been used for measurements of the F region result of the refraction is that radio waves can propagate peak electron density (André et al. 1998; Bland et al. almost perpendicular to the geomagnetic feld lines in 2014; Ponomarenko et al. 2011). To make electron den- extended regions of the high-latitude F layer, often stretch- sity estimates, elevation angles of echo arrival are con- ing from 700 to 1200 km in range. In this “quasi-orthogo- sidered. Both types of SuperDARN echoes, ionospheric nal” radio wave propagation, the presence of feld-aligned scatter (IS) and ground scatter (GS), have been used for decameter irregularities allows for return signals detectable electron density measurements. Identifcation of the ion- by radar. Of special interest are ionospheric signals cor- ospheric region for the electron density estimates is less responding to Pedersen rays. For Pedersen rays, typically certain than with the ionosondes and ISRs. For the work coming from above the F layer maximum, the returned ele- with GS signals, the region of strong radio wave bending vation angles are about the same irrespective of the radar (leading to radio waves turning toward the ground) can range. One important aspect here is that elevation angles be as large as several hundred kilometers. For IS signals, for Pedersen rays and those coming from the maximum Koustov et al. Earth, Planets and Space (2020) 72:43 Page 3 of 14 of the F layer difer insignifcantly, on the order of ~ 1°–2°. be a sphere of the radius of 6370 km) and γ is the angle Tis can be shown by ray tracing for typical ionospheric of the magnetic feld line (within the scattering volume) conditions, see for example Greenwald et al.
Load more

Recommended publications
  • Planetary Challenges & Spiritual Evolution
    Planetary Challenges & Spiritual Evolution – Citizen Summary Planetary Challenges & Spiritual Evolution Summary For Citizens of Planet Earth Written by Susan Joy Rennison, B. Sc Hons (Physics & Geophysics), June 2011 (Editorial Revision), Olten, Switzerland Copyright © 2011 Susan Joy Rennison Planetary Challenges & Spiritual Evolution – Citizen Summary Planetary Challenges & Spiritual Evolution Citizen Summary Table of Contents Table of Contents i Illustrations ii Foreword iv Introduction vii Our Sun, A Variable Star 1 The Extraordinary Quiet Solar Minimum of Solar Cycle 23 2 Space Weather & The Delivery of Evolutionary Energies 4 The Precession of the Equinoxes 5 Extreme Space Weather 6 The Gamma & Cosmic Ray Blitz From Across the Galaxy 8 The Global Warming Controversy 9 Atmospheric Change: New Electrical Manifestations 10 Extreme Physics right here on Earth 12 Asteroids, Comets & Meteors? “We’re living in a bowling alley” 13 Heavenly Phenomena: Strange Fireballs 16 The Geological Response 17 Strange Atmospheric Cloud Emissions 19 The ‘Orb’ Phenomena & ‘Diamond’ Rain 20 Earth’s Shadow Biosphere 21 The Planetary ‘Refresh’ 27 i Copyright Susan Joy Rennison Sunday, June 05, 2011 Planetary Challenges & Spiritual Evolution – Citizen Summary The ‘Upgrade’ of the Planetary Grid 31 Space Weather Drives Biological Changes 32 The Choice: Spiritual Evolution or Devolution? 33 Rapid Evolutionary Change 34 Conclusion 38 References 39 Illustrations The White House i Medieval Engraving of Gioacchino da Fiore (Joachim of Fiore) vi Space Weather Turns Into an International Problem vii The Sun −Earth Connection viii Aurora over Southern New Jersey (1989) ix Exploration of Near Earth Objects Workshop Poster x The Eventful Universe Workshop Poster xi Massive Coronal Mass Ejection Proceeding X45 Solar Flare.
    [Show full text]
  • Ionospheric Radars Development
    UNT Ionospheric radars development Enrico Zuccheretti, Umberto Sciacca [email protected] - [email protected] Istituto Nazionale di Geofisica e Vulcanologia - Rome, Italy The following slides were presented during the lectures of the course “Desarrollo de radares ionosféricos” held within the post graduate course on “Geofísica espacial” organised by the Universidad Nacional de Tucumán - Facultad de Ciencias Exactas y Tecnología - Departamento de Posgrado in Tucumán on 4 – 7 October 2010. UNT Module 1 Basics of radar theory and design elements Introduction UNT •Amongst the big variety of techniques used to study the geophysical environment, methods using electromagnetic waves occupy a very prominent position. •These techniques exploit radio waves modifications when they interact with the medium they pass through. •The ionosphere is no exception: the most common way to study its behaviour is to emit radio wave pulses into the ionosphere and to study the backscattered echo. •The echo signal contains information about the layers in which it may be refracted, reflected or absorbed. •Also signals coming from satellites (NNSS, GPS) or from terrestrial emitting station (VLF emitters) can be used. They do not exploit the radar technique but their properties are affected by the medium they pass through. Radio Frequencies Bands UNT ELF SLF ULF VLF LF MF HF VHF UHF SHF EHF 3 Hz 30 Hz 300 Hz 3 kHz 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz 30 Hz 300 Hz 3 kHz 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz 300 GHz The vertical sounding technique UNT •The measure technique is based on sending pulses of energy at different frequencies towards the ionosphere and in measuring the backscattered echo delay to properly evaluate the position of ionospheric layers.
    [Show full text]
  • Chapter 10 IONOSPHERICRADIO WAVE PROPAGATION Section 10.1 S
    Chapter 10 IONOSPHERICRADIO WAVE PROPAGATION Section 10.1 S. Basu, J. Buchau, F.J. Rich and E.J. Weber Section 10.2 E.C. Field, J.L. Heckscher, P.A. Kossey, and E.A. Lewis Section 10.3 B.S. Dandekar Section 10.4 L.F. McNamara Section 10.5 E.W. Cliver Section 10.6 G.H. Millman Section 10.7 J. Aarons and S. Basu Section 10.8 J.A. Klobuchar Section 10.9 J.A. Klobuchar Section 10.10 S. Basu, M.F. Mendillo The series of reviews presented is an attempt to introduce in HF communications is leading to a rejuvenation of the ionospheric radio wave propagation of interest to system global ionosonde network. users. Although the attempt is made to summarize the field, the individuals writing each section have oriented the work 10.1.1.1 Ionogram. Ionospheric sounders or ionosondes in the direction judged to be most important. are, in principle, HF radars that record the time of flight or We cover areas such as HF and VLF propagation where travel of a transmitted HF signal as a measure of its ionos- the ionosphere is essentially a "black box", that is, a vital pheric reflection height. By sweeping in frequency, typically part of the system. We also cover areas where the ionosphere from 0.5 to 20 MHz, an ionosonde obtains a meas- is essentially a nuisance, such as the scintillations of trans- urement of the ionospheric reflection height as a function ionospheric radio signals. of frequency. A recording of this reflection height meas- Finally, we have included a summary of the main fea- urement as a function of frequency is called an ionogram.
    [Show full text]
  • Introductionto the Ionoshpereand Geomagnetism
    N6517513 INTRODUCTION TO THE IONOSHPERE AND GEOMAGNETISM OCT 1964 SEL-64-111 INTRODUCTION TO THE IONOSPHERE AND GEOMAGNETISM by H. Rishbeth and O. K. Garriott October 1964 Reproduction in whole or in part is permitted for any purpose of the United States Government. Technical Report No. 8 Prepared under National Aeronautics and Space Administration Grant NsG 30-60 Radioscience Laboratory Stanford Electronics Laboratories Stanford University Stanford, California CONTENTS -=_:_!-_¸ Paze I. THE NEUTRAL ATMOSPHERE .................. 1 I. Atmospheric Nomenclature ............... 1 2. Evolution of the Earth's Atmosphere ......... 5 3. Structure of the Atmosphere ............. 7 4. Dissociation and Diffusive Separation ........ 12 5. Thermal Balance ................... 16 6. The Exosphere .................... 2O __J, 7. Experimental Techniques ............... 21 II. MEASUREMENT OF IONOSPHERIC PARAMETERS .......... 27 I. Introduction ..................... 27 2. Determination of Electron Density by Sounding .... 27 3, Propagation Methods ................. 36 4. Direct Measurements ................. 44 z, 5. Incoherent Scatter .................. 46 III. PROCESSES IN THE IONOSPHERE ............... 50 I. The Balance of Ionization .............. 50 2. Chapman's Theory ................... 53 3. Production and Loss ................. 63 4. The D, E and F1 Photochemical Regime ....... 69 5. Plasma Diffusion ................... 81 6. Solving the Continuity Equation ........... 88 IV. MORPHOLOGY OF THE IONOSPHERE 94 1. D Region .................... 94 2.
    [Show full text]
  • Midlatitude D Region Variations Measured from Broadband Radio Atmospherics
    MIDLATITUDE D REGION VARIATIONS MEASURED FROM BROADBAND RADIO ATMOSPHERICS by Feng Han Department of Electrical and Computer Engineering Duke University Date: Approved: Steven A. Cummer, Advisor David R. Smith Qing H. Liu William T. Joines Thomas P. Witelski Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Electrical and Computer Engineering in the Graduate School of Duke University 2011 Abstract (Electrical and Computer Engineering) MIDLATITUDE D REGION VARIATIONS MEASURED FROM BROADBAND RADIO ATMOSPHERICS by Feng Han Department of Electrical and Computer Engineering Duke University Date: Approved: Steven A. Cummer, Advisor David R. Smith Qing H. Liu William T. Joines Thomas P. Witelski An abstract of a dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Electrical and Computer Engineering in the Graduate School of Duke University 2011 Copyright c 2011 by Feng Han All rights reserved except the rights granted by the Creative Commons Attribution-Noncommercial Licence Abstract The high power, broadband very low frequency (VLF, 3{30 kHz) and extremely low frequency (ELF, 3{3000 Hz) electromagnetic waves generated by lightning dis- charges and propagating in the Earth-ionosphere waveguide can be used to measure the average electron density profile of the lower ionosphere (D region) across the wave propagation path due to several reflections by the upper boundary (lower iono- sphere) of the waveguide. This capability makes it possible to frequently and even continuously monitor the D region electron density profile variations over geograph- ically large regions, which are measurements that are essentially impossible by other means.
    [Show full text]
  • Of Airglow Associated with Medium-Scale Traveling Ionospheric Disturbance
    PUBLICATIONS Journal of Geophysical Research: Space Physics RESEARCH ARTICLE Mesoscale field-aligned irregularity structures (FAIs) 10.1002/2014JA020944 of airglow associated with medium-scale traveling Key Points: ionospheric disturbances (MSTIDs) • An evolution of medium-scale traveling ionospheric disturbances Longchang Sun1,2, Jiyao Xu1, Wenbin Wang3, Xinan Yue4, Wei Yuan1, Baiqi Ning5, Donghe Zhang6, (MSTIDs) is presented 1 • Mesoscale field-aligned irregularity and F. C. de Meneses structures (FAIs) (~150 km) of airglow 1 are firstly presented State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China, • We first find the mesoscale FAIs had a 2Graduate University of the Chinese Academy of Sciences, Beijing, China, 3High Altitude Observatory, National Center for northwestward relative velocity to Atmospheric Research, Boulder, Colorado, USA, 4COSMIC Program Office, University Corporation for Atmospheric Research, main-body MSTIDs Boulder, Colorado, USA, 5Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China, 6Department of Geophysics, Peking University, Beijing, China Correspondence to: fi L. Sun, Abstract In this paper, we report the evolution (generation, ampli cation, and dissipation) of optically [email protected] observed mesoscale field-aligned irregularity structures (FAIs) (~150 km) associated with a medium-scale traveling ionospheric disturbance (MSTID) event. There have not been observations of mesoscale FAIs of Citation: airglow before. The mesoscale FAIs were generated in an airglow-depleted front of southwestward propagating Sun, L., J. Xu, W. Wang, X. Yue, W. Yuan, MSTIDs that were simultaneously observed by an all-sky imager, a GPS monitor, and a digisonde around B. Ning, D. Zhang, and F. C. de Meneses Xinglong (40.4°N, 30.5° magnetic latitude), China, on 17/18 February 2012.
    [Show full text]
  • INDIA JANUARY 2018 – June 2020
    SPACE RESEARCH IN INDIA JANUARY 2018 – June 2020 Presented to 43rd COSPAR Scientific Assembly, Sydney, Australia | Jan 28–Feb 4, 2021 SPACE RESEARCH IN INDIA January 2018 – June 2020 A Report of the Indian National Committee for Space Research (INCOSPAR) Indian National Science Academy (INSA) Indian Space Research Organization (ISRO) For the 43rd COSPAR Scientific Assembly 28 January – 4 Febuary 2021 Sydney, Australia INDIAN SPACE RESEARCH ORGANISATION BENGALURU 2 Compiled and Edited by Mohammad Hasan Space Science Program Office ISRO HQ, Bengalure Enquiries to: Space Science Programme Office ISRO Headquarters Antariksh Bhavan, New BEL Road Bengaluru 560 231. Karnataka, India E-mail: [email protected] Cover Page Images: Upper: Colour composite picture of face-on spiral galaxy M 74 - from UVIT onboard AstroSat. Here blue colour represent image in far ultraviolet and green colour represent image in near ultraviolet.The spiral arms show the young stars that are copious emitters of ultraviolet light. Lower: Sarabhai crater as imaged by Terrain Mapping Camera-2 (TMC-2)onboard Chandrayaan-2 Orbiter.TMC-2 provides images (0.4μm to 0.85μm) at 5m spatial resolution 3 INDEX 4 FOREWORD PREFACE With great pleasure I introduce the report on Space Research in India, prepared for the 43rd COSPAR Scientific Assembly, 28 January – 4 February 2021, Sydney, Australia, by the Indian National Committee for Space Research (INCOSPAR), Indian National Science Academy (INSA), and Indian Space Research Organization (ISRO). The report gives an overview of the important accomplishments, achievements and research activities conducted in India in several areas of near- Earth space, Sun, Planetary science, and Astrophysics for the duration of two and half years (Jan 2018 – June 2020).
    [Show full text]
  • CC 149XX7 Next Generation Ionosonde (NEXION)
    Next Generation Ionosonde (NEXION), (DPS 4-D). FAC: 1341 CATCODE: 149XX7 OPR: AFWA/A5/A8, MAJCOM/A3W OCR: MAJCOM/A6 1.1. Description. NEXION is an unmanned ionosonde facility that supports activities to sense and report ionospheric information for comprehensive and ongoing environmental analysis and mission impact assessment. NEXION is vertical incidence radar used to obtain information about the ionosphere directly overhead and consists of 30 systems worldwide and one test system. NEXION provides a 24/7 remote monitoring capability of the ionosphere by analyzing the signals reflected from the ionosphere and providing data to AFWA via the NIPRNet to be ingested into the new generation of Global Assimilation of Ionospheric Measurements (GAIM). 1.2. Requirements Determination. This facility supports activities and equipment to sense and report ionospheric information 24/7 to support and maintain battlespace awareness. Obtain further information through AFWA/A5/8 or MAJCOM/A3 weather staff. 1.3. Scope Determination. A NEXION site consists of a support building consisting of approximately 5 m2 (50 ft2), four receiving antennas placed in a triangular 60 degree configuration 60 m (197 ft) apart with #2 and #3 antennas aligned to magnetic north, and the #1 antenna centered between antennas #2 and #3 but physically located 34.64 m (114 ft) to the west of antenna #4. See Figure 1.2 for alignment and placement. Distance between the transmit tower and receiver antennas is 30 m (98.4 ft) minimum separation. The transmit antenna requires 15.24 m (50 ft) clearance between the transmit antenna and potential obstructions such as trees, shrubs, etc.
    [Show full text]
  • Article E Layer
    Geosci. Instrum. Method. Data Syst., 5, 53–64, 2016 www.geosci-instrum-method-data-syst.net/5/53/2016/ doi:10.5194/gi-5-53-2016 © Author(s) 2016. CC Attribution 3.0 License. Comparison between manual scaling and Autoscala automatic scaling applied to Sodankylä Geophysical Observatory ionograms Carl-Fredrik Enell1, Alexander Kozlovsky2, Tauno Turunen2,*, Thomas Ulich2, Sirkku Välitalo2, Carlo Scotto3, and Michael Pezzopane3 1EISCAT Scientific Association, Kiruna, Sweden 2Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland 3Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy *retired Correspondence to: Carl-Fredrik Enell ([email protected]) Received: 16 November 2015 – Published in Geosci. Instrum. Method. Data Syst. Discuss.: 21 December 2015 Revised: 14 March 2016 – Accepted: 14 March 2016 – Published: 23 March 2016 Abstract. This paper presents a comparison between stan- 1 Introduction dard ionospheric parameters manually and automatically scaled from ionograms recorded at the high-latitude So- dankylä Geophysical Observatory (SGO, ionosonde SO166, Ionosondes for studying the ionosphere were invented in the 64.1◦ geomagnetic latitude), located in the vicinity of the au- late 1920s, and their worldwide implementation started in the roral oval. The study is based on 2610 ionograms recorded 1940s as military shortwave communication became impor- during the period June–December 2013. The automatic scal- tant. An ionosonde is a radio echo instrument transmitting ra- ing was made by means of the Autoscala software. A few dio waves of alternating frequency, receiving reflections from typical examples are shown to outline the method, and statis- the ionosphere, and measuring the travel times of the waves tics are presented regarding the differences between manu- at different frequencies.
    [Show full text]
  • A History of Vertical-Incidence Ionsphere Sounding at the National
    TECH, aoaot Mii22 PB 151387 ^0.28 ^5oulder laboratories A HISTORY OF VERTICAL - INCIDENCE IONOSPHERE SOUNDING AT THE NATIONAL BUREAU OF STANDARDS BY SANFORD C. GLADDEN U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS IE NATIONAL BUREAU OF STANDARDS Functions and Activities The Functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards: the determination of physical constants and properties of materials: the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; in- vention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic and applied research, development, engineering, instrumentation, testing, evaluation, calibration services, and various consultation and information services. Research projects are also performed for other government agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau's unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover. Publications The results of the Bureau's work take the form of either actual equipment and devices or pub- lished papers. These papers appear either in the Bureau's own series of publications or in the journals of professional and scientific societies.
    [Show full text]
  • Low Cost Low Power Ionosonde for Dense Sensor Networks
    Low cost low power ionosonde for dense sensor networks Juha Vierinen, David L. Hysell, Marco Milla, Jorge L. Chau and Frank D. Lind MIT Haystack Observatory Sodankyl¨aGeophysical Observatory, Finland Cornell University Jicamarca Radio Observatory, Peru December 3, 2013 Previous work I A lot of previous work, starting from Hertz, Marconi, Heaviside, Breit and Tuve (1926), Lassen (1926), Appleton (1931)... I Many, many others (eg., Budden 1961, Jones and Stephenson 1975). I Monitoring traveling ionospheric disturbances (Crowley and Rodrigues 2012, Crowley et al., 1987) Software defined chirp ionosonde receiver Video (virg.mp4,cyprus.mp4) Multi-static HF radar equation Continuous coded transmission I Continuous transmit and receive, cyclic convolution assumption valid due to long coherence I Multiple simultaneous transmitters using the same channel. I Perfect codes exist for T = 1 (Frank and Chu codes) I Pseudorandom sequences are very close to optimal for R N. 3D electron density inversion using HF radio propagation Airplane Low cost ionosonde I With a small change in software, and an antenna tuner, the radar would effectively be an ionosonde. I If an ionosonde could be made as cheap as a GPS TEC receiver, there would be a possibility to operate a dense network of ionosondes and get high quality ionospheric profiles. I A low power ionosonde that basically transmits noise wouldn't cause as much interference to others, and it would be more easy to license. I The orthogonality of pseudorandom signals would allow oblique soundings between ionosondes within a network { and again, with the help of ray-tracing, the study of even smaller spatial scales.
    [Show full text]
  • Comparison of EISCAT and Ionosonde Electron Densities: Application to a Ground-Based Ionospheric Segment of a Space Weather Programme
    Annales Geophysicae (2005) 23: 183–189 SRef-ID: 1432-0576/ag/2005-23-183 Annales © European Geosciences Union 2005 Geophysicae Comparison of EISCAT and ionosonde electron densities: application to a ground-based ionospheric segment of a space weather programme J. Lilensten1, Lj. R. Cander2, M. T. Rietveld3, P. S. Cannon4, and M. Barthel´ emy´ 1 1Laboratoire de Planetologie´ de Grenoble, France 2Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK 3EISCAT Association, Norway 4QinetiQ, Malvern, Worcs, WR14 3PS, UK Received: 3 October 2003 – Revised: 11 August 2004 – Accepted: 6 October 2004 – Published: 31 January 2005 Part of Special Issue “Eleventh International EISCAT Workshop” Abstract. Space weather applications require real-time data 2001, is studying the influences of both the Sun and the and wide area observations from both ground- and space- anthropogenic effects on the mesosphere and lower thermo- based instrumentation. From space, the global navigation sphere/ionosphere. It includes four instruments, of which the satellite system – GPS – is an important tool. From the Doppler Interferometer (TIDI) globally measures wind and ground the incoherent scatter (IS) radar technique permits a temperature profiles to investigate the dynamics and energy direct measurement up to the topside region, while ionoson- balance of the Earth’s mesosphere and lower-thermosphere. des give good measurements of the lower part of the iono- However, the upper altitude of the TIDI experiment is only sphere. An important issue is the intercalibration of these 180 km, which is relatively low and for most space weather various instruments. applications it is necessary to use thermospheric models, cal- In this paper, we address the intercomparison of the EIS- ibrated via indirect (proxy) measurements (Lilensten, 2001).
    [Show full text]