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.
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Showing 1 to 20 of 69 for “"Solar activity"”.
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Solar activity and middle atmospheric dynamics
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1987.
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Solar-activity-based neutral hydrogen geocorona model
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01
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Solar activity variations of the ionospheres of Venus and Mars
… the atmosphere of a planet called an ionosphere. Solar activity, including solar flares, coronal mass ejections, and changes in the ionizing irradiance affect planetary ionospheres on short and long timescales. These effects are significant because the ionosphere is a reservoir from which …
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The dependence of the circulation of the thermosphere on solar activity
Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology.
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Solar activity detection and prediction using image processing and machine learning techniques
… for automatic detection and prediction of solar activities, including prominence eruptions, emerging flux regions and solar flares. Image processing and machine learning techniques are applied in this study. These methods can be used for automatic observation of solar activities and …
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An investigation into the phenomenological relation between solar activity and nuclear beta-decay rates
… algorithms to identify regions of anomalous activity in a nuclear decay signal. With stringent threshold cut-offs and filtering processes, these regions are isolated as exhibiting statistically significant deviations from an expected exponential decay model. The isolated decay flags are …
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GPS positioning improvement by mitigating the ionospheric horizontal gradient
… baselines length (short and long), low and high solar activity, range measurement from three and eight satellites and two different duration times (one and three hours). Some improvements can be seen after the corrections and it was a noticeable positioning improvement at the user location over …
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Dynamics of filaments, flares and coronal mass ejections (CMEs)
… the connection between the dynamics of solar surface phenomena such as filament eruptions, flares, the coronal mass ejections (CMEs), the core of so-called solar activity, and the properties of the associated magnetic field for the development of forecasts of solar activity and space …
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Investigations of temporal changes in climate and the geomagnetic field via high-resolution radiocarbon dating
… has been interpreted to be a result of decreased solar activity. Therefore, a solar-induced climate change has been suggested. In addition to changes in solar activity, geomagnetic field records also show prominent variations around 3000-2000 cal BP. In order to investigate the temporal …
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Analysis of a CubeSat Orbit Using STK
… communication performance. The influence of solar activity on CubeSat lifetime and access time was examined, highlighting the significance of mass and solar activity. The impact of increasing orbit size on communication time was analyzed, emphasizing the trade-offs between mass, orbit size, …
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Análise de observações do diâmetro no contexto da atividade solar
From 1997 to 2003 the CCD Solar Astrolabe of the Observatório Nacional in Rio de Janeiro made more than 20,000 observations of the Solar Semidiameter. The experimental data from1998 to 2001 had been obtained in two independent previous works, by the corrections of the systematic effects on the raw …
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Spatial Resolution of Equatorial Plasma Depletions Using Variable-Range Time-Delay Integration
… Additionally, the effects of depletion width, solar activity level, and misalignment of the field-of-view with the local magnetic field were investigated. The variable-range TDI technique is able to recover the overall shape and depth of depletion of the depletions in all cases, however the …
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Automatic solar feature detection using image processing and pattern recognition techniques
… system to automatically detect and characterize solar flares, filaments and Corona Mass Ejections (CMEs), the core of so-called solar activity. These tools will assist us to predict space weather caused by violent solar activity. Image processing and pattern recognition techniques are applied to …
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Synoptic variability of a CIR-driven open-closed boundary during solar minimum
… year 2008 marked a historically quiet period of solar activity during the declining phase of solar cycle 23. Such quiet time has permitted researchers to clearly distinguish the spectral signature of a corotating interaction region's (CIR) impact on the open-closed boundary (OCB) of the …
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A global and tropical quasi-decadal oscillation of the atmosphere and Ocean
… The oscillation was found to be unrelated to the solar activity cycle, while it displayed coherence with similar oscillatory signals in ENSO, PDO and AMO indices, as well as with a quasi-decadal signal in SST data. Finally, the quasi-decadal signal in lower stratospheric temperature was found to …
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On the Variation of Gravity Wave Activity through the Solar Cycle at the South Pole
… driver of atmospheric dynamics. The 11-year solar cycle of the sun has had a noticeable effect on the overall climate of the earth in the past. More recent work has seen the diurnal tides being directly influenced by the change in solar energy over the solar cycle at the South Pole. The …
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Comparison and Investigation of Solar Spectral Irradiance with Solar Aspect Monitor
… thermosphere is derived. The uniquely stable solar activity during 2010 allows the local time variation of NO to be observed with limited influence of solar variability. The comparison with a 1D model shows good agreement at altitude above 120 km, suggesting that most of the local time …
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Direct and Indirect Searches for Anomalous Beta Decay
… of several isotopes may have been influenced by solar activity (perhaps by solar neutrinos). A mechanism in which (anti)neutrinos can influence the decay process suggests that a sample of decaying nuclei emitting neutrinos could affect its own rate of decay. Past experiments have searched for …
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