Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 20 for “"Ionospheric Disturbances"”.
-
Ionospheric Disturbances: Midlatitude Pi2 Magnetospheric ULF Pulsations and Medium Scale Traveling Ionospheric Disturbances
… magnetosphere, and the neutral atmosphere. The ionospheric state can significantly impact technological systems, especially those which utilize radio frequency energy. By studying ionospheric disturbances, it is possible to gain a deeper understanding of not only the ionosphere itself, but also …
-
A sudden ionospheric disturbances monitor
Sudden Ionospheric Disturbances are the immediate effects of solar flares, which impact the earth, and affect the upper atmospheric layers used for telecommunications. The aim of this project was to research, design and build a sudden ionospheric Disturbance Monitor for amplitude and phase …
-
The Co-Volcanic Ionospheric Disturbances at Mt.Etna, Italy
… and navigation, are now widely used for ionospheric sounding. Due to the dispersive nature for radio waves, the ionosphere affects the GNSS signals as a function of its electron density. By this condition the total electron content (TEC) of the ionosphere can be estimated from GNSS data. …
-
Medium Scale Travelling Ionospheric Disturbances sensed with GNSS TEC and SuperDARN
Medium Scale Travelling Ionospheric Disturbances (MSTIDs) are quasi-wavelike structures in ionospheric density that can be sensed using Global Navigational Satellite Service (GNSS) Total Electron Content (TEC) techniques and coherent scatter radars such as the Super Dual Auroral Radar Network …
-
An Investigation of Large-Scale Traveling Ionospheric Disturbances Observed in a Radiolocation Experiment
Made available in DSpace on 2014-12-08T22:23:50Z (GMT). No. of bitstreams: 1 6604165.pdf: 4210652 bytes, checksum: ae113d80360ab9d3fef9dce77e4b3d1d (MD5) Previous issue date: 1965
-
An Investigation of Directional Deviations of Steeply Downcoming Hf Radiowaves Due to Traveling Ionospheric Disturbances
Made available in DSpace on 2014-12-10T19:06:54Z (GMT). No. of bitstreams: 1 7212423.pdf: 4652952 bytes, checksum: d9ff2ea5a9299f61d3fe04a6ab80c691 (MD5) Previous issue date: 1971
-
Observations and numerical simulations of electrified, medium-scale traveling ionospheric disturbances (MSTIDs) in the nighttime, mid-latitude ionosphere
… physical understanding of medium-scale traveling ionospheric disturbances (MSTIDs). This will be accomplished primarily through an observational study and with the aid of numerical simulations. MSTIDs are instabilities in the ionosphere characterized by vertical displacements in electron density …
-
SIMULATED GPS OBSERVATION OF TRAVELING IONOSPHERIC DISTURBANCE FROM GROUND BASED RECEIVERS
Traveling Ionospheric Disturbances (TID) can be induced by acoustic waves in
-
Three-Dimensional Tomographic Imaging of the Ionosphere Using Global Positioning System Measurements
… classes of structures: equatorial-originating ionospheric depletions and mesoscale traveling ionospheric disturbances (MS-TIDs). A time-series of reconstructed images unravels the evolution and movement of ionospheric structures through the reconstruction region. Lastly, simulations demonstrate …
-
Radio and Optical Techniques for Locating Equatorial Plasma Irregularities
… of kilometers. Spread-F, the disruption of ionospheric measurements with ionosondes and incoherent scatter radar, and scintillation (fading) of trans-ionospheric radio communication and navigation signals are well-known symptoms of depletions. This dissertation describes new techniques to …
-
Growth rate simulations of instability mechanisms at low and mid-latitudes for explaining equatorial spread F
One of the ongoing fields of ionospheric research is studying the characteristics and behavior of Equatorial Spread F (ESF). The general seasonalities of ESF occurrence are well known, but much work remains to be done in learning its day--to--day variability. Understanding the complexities of the …
-
Techniques for automated classification of nighttime ionospheric images
… and Chile is being collected in order to study ionospheric structures. The images of interest are those that contain equatorial plasma bubbles (EPB) or medium-scale traveling ionospheric disturbances (MSTID). However the majority of the images collected contain neither EPBs nor MSTIDs, or are …
-
Theoretical and Experimental Study of Gravity Waves in the Ionosphere Observed With Incoherent Scatter Radar
… waves observed in the ionosphere was studied. Ionospheric parameters observed with the incoherent scatter radars at Sondrestrom and Millstone Hill were compared with predicted results based on gravity wave theory. In the observed data, usually two types of disturbances can be identified. One is …
-
Influence of lightning on electron density variation in the ionosphere using WWLLN lightning data and GPS data
… of wave-like structures in the form of Traveling Ionospheric Disturbances (TID) in the ionosphere and tropospheric lightning in the mid-latitude region over South Africa. Lightning induced changes in total electron content (TEC) are strongest between September and March, with the more-pronounced …
-
Could global warming affect space weather? : case studies of intense ionospheric plasma turbulence associated with natural heat sources
… on observations of a series of highly-structured ionospheric plasma turbulence over Arecibo on the nights of 22/23 and 23/24 July, 2006. Incoherent scatter measurements by Arecibo radar, airglow measurements using MIT PSFC's all-sky imaging system (ASIS), together with TEC measurements from GPS …
-
Generation of acoustic-gravity waves in ionospheric HF heating experiments : simulating large-scale natural heat sources
… trigger widespread plasma turbulence in the ionospheric layer. The main hypothesis is that, the thermal gradients associated with the heat wave fronts could act as a source of powerful AGW capable of triggering ionospheric plasma turbulence over extensive areas. In our investigations, first …
-
Design of an HF transmit antenna for bistatic ionospheric soundings in Antarctica
Studying high-latitude travelling ionospheric disturbances (TIDs) is of importance be-cause they often correspond to space weather events which affect the earth's climate. The South African National Space Agency (SANSA) plans to install a low-powered high frequency (HF) transmitter at the South …
-
Atmospheric and Ionospheric Responses to Acoustic and Gravity Waves Driven by Earthquakes and Tsunamis
… and their effects on mesopause airglow and ionospheric plasma.</p> <p>First, we examine coupling mechanisms based on case studies for two inland earthquakes. We demonstrate that the incorporation of near-epicentral seismic wave dynamics, based on earthquake finite-fault models, provides …
-
Characterising Spatial and Temporal Ionospheric Variability with a Network of Oblique Angle-of-arrival and Doppler Ionosondes
Ionospheric variability exists on a broad range of scales, and routinely impacts skywave propagation modes of high frequency radio waves, to the detriment of radar and communication systems. In order to better understand the electron density structures associated with such variability at …