1. BELGRADE DATABASES - ionospheric observations and detections astro- and geophysical phenomena by radio signals Aleksandra Nina Institute of Physics, Belgrade BSE Belgrade, 2015

2. Contents 22 Introduction - D-region - VLF/LF signals Belgrade VLF/LF receiver stationBelgrade VLF/LF receiver station Databases – characteristics and importanceDatabases – characteristics and importance Investigations based on our databasesInvestigations based on our databases Department of Telecommunication and Information ScienceLaboratory for investigations of influences of astro- and geophysical events on telecommunication signals - Department of Telecommunication and Information Science Summary BSE Belgrade, 2015

3. Institute of Physics Belgrade Astronomical observatory Belgrade Aleksandra Nina Vladimir Srećković Vladimir Čadež Luka Popović Darko Jevremović Jovan Bajčetić Aleksandra Kolarski

4. h (km) magnetosphere ozone layer Atmospheric boundary layer Introduction – D-region LOCATION 4 DIAGNOSTIC METHODES rockets radio signals radars 4 IMPORTANCE The lowest daytime ionospheric region (50 km – 90 km) Science Telecommunications Elementary disaster predictions BSE Belgrade, 2015

5. Introduction – VLF/LF signals FREQUENCY DOMAINFREQUENCY DOMAIN VLF 3 kHz – 30 kHz; LF 30 kHz – 300 kHz VLF/LF SIGNAL PROPAGATIONVLF/LF SIGNAL PROPAGATION Earth – ionosphere waveguide GLOBAL SETTINGSGLOBAL SETTINGS -transmitters -receivers it allows the analyses of large part of D-region and detection of local perturbations CONTINUOUS SENDING AND RECEIVING OF SIGNALSCONTINUOUS SENDING AND RECEIVING OF SIGNALS - it allows detections of unperiodical perturbations it allows detections of unperiodical perturbations 5 BSE Belgrade, 2015

6. AbsPAL Belgrade VLF/LF receiver station 6 6 BSE Belgrade, 2015 (AtmosphericWeather Electromagnetic System for Observation Modeling and Education) (Absolute Phase and Amplitude Logger) AWESOME Operable since: 2003 2008 Simultaneously monitor: 5 signals 15 signals Time resolutions: 0.1 s 0.02 s During this period we have collected a large database containing a written information about numerous low ionospheric responses to different natural and human induced events.

7. global ionospheric investigationglobal ionospheric investigation studies of influences of different events – comparisons with other databasesstudies of influences of different events – comparisons with other databases Contributions in Experimental data related to consideredExperimental data related to considered locations and time periods for study particular cases Experimental data for a lot of cases for statistical analysesExperimental data for a lot of cases for statistical analyses Two identical cases cannot be occurredTwo identical cases cannot be occurred Medium properties and perturbers characteristics are very complexMedium properties and perturbers characteristics are very complex Time and space dependent parameters (several order of magnitude)Time and space dependent parameters (several order of magnitude) h (km) magnetosphere ozone layer Atmospheric boundary layer satelite databases outer space satelite databases uper ionosphere databases low atmosphere VLF/LF DATABASES BSE Belgrade, 2015 Databases – importance 7 Belgrade databases will be available

8. Examples of events recorded by Belgrade VLF/LF station - Developed procedures

9. Detectability of strong perturbations Lyα Periodical perturbations X-flares- X-flares- sudden perturbations 9

10. Development procedures for calculations different plasma parameters Thermal science Accepted paper -Electron density -Rate of electron gain processes -Rate of electron loss processes -Lyα photoionization rate -Temperature -Effective recombination coefficient -Electron plasma frequency -Refractive index for EM waves -Periods of hydrodynamic waves Advances in Space Research Volume 54, Issue 7Volume 54, Issue 7, 1 October 2014, Pages 1276–1284 Spectral line shapes in astrophysics and related phenomena

11. Development procedures for -Detection of events that weakly ionize plasma in low ionosphere -Detection of hydrodynamic waves in low ionosphere

12. Influence of astro- and geophysical events on telecommunication signals Thermal science Accepted paper IEEE Geoscience and remote sensing letters Submitted paper

13. Department of Telecommunication and Information Science Investigations of influences of astro- and geophysical events on telecommunication signals Frequency domains: 10kHz – 6.2GHz Forming of laboratory is in progress We will have continuous measurements Databases will be formed University of Defence Belgrade

14. Ionospheric variations and natural disasters predictions Kraljevo (43.74 N, 20.69 E), November 3, 2010 Earthquake Cyclon

15. Summary Experimental setups for ionospheric observations and detections astro- and geophysical phenomena by radio signals Databases: characteristics and importance in SCIENCE TELECOMMUNICATIONS NATURAL DISASTERS PROCEDURES ARE DEVELOPED FOR: 1.Calculations different low ionospheric plasma parameters 2.Examination possibilities of applying VLF signal technology to detection of events that weakly ionize plasma in low ionosphere. 3.Detection of hydrodynamic waves in low ionosphere using VLF signals for ionospheric monitoring. 4.Calculations parameters for propagation of telecommunication signals under unperturbed and perturbed conditions in low ionosphere 15

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