Дисертації з теми "Solar variations"
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Walker, Catherine C. "Variations of solar wind parameters over a solar cycle : expectations for NASA's Solar TErrestrial RElations Observatory (STEREO) mission /." Connect to online version, 2007. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2007/226.pdf.
Повний текст джерелаJonson, Martin. "On density and pressure variations in the solar wind plasma." Thesis, KTH, Rymd- och plasmafysik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91825.
Повний текст джерелаSharma, Pratibha. "Modeling, Optimization, and Characterization of High Concentration Photovoltaic Systems Using Multijunction Solar Cells." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35917.
Повний текст джерелаJacobi, Christoph, Norbert Jakowski, Gerhard Schmidtke, and Thomas N. Woods. "Delayed response of the global total electron content to solar EUV variations." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-212283.
Повний текст джерелаHood, L. L., and B. E. Soukharev. "Solar induced variations of odd nitrogen: Multiple regression analysis of UARS HALOE data." AMER GEOPHYSICAL UNION, 2006. http://hdl.handle.net/10150/623348.
Повний текст джерелаOrtiz, Carbonell Ada Natalia. "Solar Irradiance Variations Induced by Faculae and Small Magnetic Elements in the Photosphere." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/733.
Повний текст джерелаIrradiance variations produced on the solar rotation time-scale are due to the passage of active regions across the solar disk. However, the origin of variations on the solar cycle time-scale is under debate. One of the most controversial aspects is the long-term contribution of the small magnetic elements conforming faculae and the network. Their identification and contrast measurement is difficult and, consequently, their contrast center-to-limb variation (CLV) remains poorly defined in spite of the fact that its knowledge is essential to determine their contribution to variability.
In this work we have studied the contribution of small photospheric magnetic elements (those with a positive contribution to variability), both on short, i.e. solar rotation, and long, i.e. solar cycle, time-scales. By analyzing the evolution of an isolated active region (NOAA AR 7978) during several Carrington rotations, we have evaluated the variations in luminosity induced by this facular region during the 1996 minimum of activity. Simultaneous photometric and magnetic data from the MDI instrument have been combined in order to study the contrast of small scale magnetic features and its dependence both on position and magnetic field, as well as its evolution along the rising phase of solar cycle 23.
The study of the solar variability has required reduction and analysis of the employed MDI and VIRGO data. These data had to be converted from level 0 (raw data) to level 2 (scientifically useful data), since solar variations were hidden by instrumental effects. We developed original algorithms to correct instrument-related effects from the data, such as filter degradation and the variation of the limb darkening with distance. The determination of the contrast of magnetic features also required the development of an algorithm in order to identify the surface distribution of those small features present over the solar disk.
By analyzing irradiance variations induced by the small magnetic features that emerge into the solar photosphere we have concluded that:
· active region faculae and the magnetic network present very different contrast CLV's, therefore, their contributions to irradiance variability are distinct; as a consequence, both contributions need to be taken into account separately when reconstructing variations of the solar irradiance.
· the functional dependence on position and magnetic signal of the facular contrast is time independent; this suggests that the physical properties of the underlying flux tubes do not vary with time.
· network elements are bright over the whole solar disk and have proved to be the dominant population along the solar cycle; this implies that their contribution to long-term irradiance variations is significant and needs to be taken into account.
Hood, L. L., and S. Zhou. "Stratospheric effects of 27-day solar ultraviolet variations: The column ozone response and comparisons of solar cycles 21 and 22." AMER GEOPHYSICAL UNION, 1999. http://hdl.handle.net/10150/624008.
Повний текст джерелаHood, L. L. "Lagged response of tropical tropospheric temperature to solar ultraviolet variations on intraseasonal time scales." AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/623304.
Повний текст джерелаMontenegro, Cristian Fernando Torres. "Modelling of utility-scale PV systems and effects of solar irradiance variations on voltage levels." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-24032017-132931/.
Повний текст джерелаEste trabalho apresenta um modelo dinâmico de sistemas fotovoltaicos de grande escala. O modelo é baseado em uma topologia de conversor centralizado, que usa um conversor de fonte de tensão (VSC) para facilitar a troca de energia entre os geradores fotovoltaicos e a rede elétrica. O sistema de controle relacionado regula a energia ativa e reativa injetada pelo sistema fotovoltaico, com base em uma estratégia de controle de corrente. Além disso, o modelo inclui um sistema de rastreamento de ponto de potência máxima (MPPT), implementado com o método da condutância incremental. O dimensionamento do modelo é apresentado, bem como vários casos de simulação para validar o seu desempenho. Posteriormente, o modelo foi utilizado para analisar o efeito das variações na radiação solar sobre uma rede de teste com uma elevada penetração de geração fotovoltaica. Os resultados mostraram que sem uma adequada compensação de energia reativa, as variações na radiação solar podem causar flutuações de tensão fora dos limites permitidos. Assim, a fim de mitigar estas flutuações, estratégias de controle local foram implementadas para permitir a troca de potência reativa entre os sistemas fotovoltaicos e a rede. As simulações mostraram que as estratégias propostas podem mitigar as flutuações de tensão no ponto de acoplamento comum, melhorando a regulação de tensão na rede.
Austin, J., L. L. Hood, and B. E. Soukharev. "Solar cycle variations of stratospheric ozone and temperature in simulations of a coupled chemistry-climate model." COPERNICUS, 2007. http://hdl.handle.net/10150/623329.
Повний текст джерелаSikkema, Hendrick A. "The role of solar wind pressure variations in the appearance of near-relativistic electrons near geostationary orbit." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ59877.pdf.
Повний текст джерелаHood, L. L., and S. Zhou. "Stratospheric effects of 27-day solar ultraviolet variations: An analysis of UARS MLS ozone and temperature data." AMER GEOPHYSICAL UNION, 1998. http://hdl.handle.net/10150/624009.
Повний текст джерелаZhou, Shuntai, Alvin J. Miller, and Lon L. Hood. "A partial correlation analysis of the stratospheric ozone response to 27-day solar UV variations with temperature effect removed." AMER GEOPHYSICAL UNION, 2000. http://hdl.handle.net/10150/624005.
Повний текст джерелаJenkins, Jon Michael. "Variations in the 13 cm opacity below the main cloud layer in the atmosphere of Venus inferred from Pioneer-Venus radio occultation studies 1978-1987." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/14843.
Повний текст джерелаSakai, Tadashi. "A Study of Variable Thrust, Variable Specific Impulse Trajectories for Solar System Exploration." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4904.
Повний текст джерелаLundin, Johan. "EROI of crystalline silicon photovoltaics : Variations under different assumptions regarding manufacturing energy inputs and energy output." Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-199639.
Повний текст джерелаSmirès, Najib. "Contribution des mesures lidar à l'études des variations à long terme de l'état thermique de l'atmosphère moyenne." Paris 6, 1986. http://www.theses.fr/1986PA066434.
Повний текст джерелаFoster, Simon Steven. "Reconstruction of solar irradiance variations for use in studies of global climate change : application of recent SoHO observations with historic data from the Greenwich Observatory." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408976.
Повний текст джерелаRodrigues, Paulo Roberto Grangeiro. "Astrologia e personalidade: o efeito do conhecimento das características do signo solar em variáveis medidas pelo 16 pf." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/47/47134/tde-20092004-172927/.
Повний текст джерелаIn this thesis we constructively replicate an european research that found for astrology knowledgeable subjects higher means on Extraversion among subjects of Fire and Air signs, compared with subjects of Earth and Water, compound a saw-tooth pattern due the zodiacal alternation between signs of Hot (Fire and Air) and Cold (Earth and Water) Elements, as an effect of the self-attribution, since the same variation was not found for no knowledgeable subjets. Also was found, however, a difference on susceptibility to information about their personality from outside for the Hots, what didnt invalidate totally the astrological theory. That research found, furthermore, higher mean in Extraversion for that knowledgeable subjects. We applied the 16PF Test Sixteen Personality Factor Questionnaire to 589 brazilian subjects of both sexes, classifying between knowledgeable (208) and no knowledgeable (381) of astrology, being this knowledge constituted by the believe in astrology and by the naming of three characteristics that go with the sunsign. In order to trigger the self-attribution effect, part of the group (266) was given the cue This is a research into astrology, while to the other part was given research into personality. We investigate variations by dependence on the astrological Elements, by the Analysis of Variance (ANOVA), on all the 16 PF factors, more Extraversion, Anxiety and Control. Didn´t appear significant differences to the Extraversion alone, yet among the knowledgeable. The knowledgeable subjects describe theirselves significantly as having higher Extraversion and Anxiety, suggesting an external locus of control, by comparision with the no knowledgeable. It was confirmed that for the knowledgeable the higher general mean in Extraversion is due to the subjects pertaining to the subgroup of the Hot signs, and the higher general mean in Anxiety is due to the subjects pertaining to the subgroup of the Cold signs, indicating a confirmation of the higher susceptibility to information about their personality from outside among the Hots. We investigate, furthermore, if the astrological self-attribution affects not only the self-concept, but also the actual performance, with the 13 items of Intelligence in the 16PF. For the no knowledgeable group the Anxiety was higher for the Hots than to the Colds due to their components Emotional Estability and Tension. This finding pointed to that Anxiety, as a non-intellective factor, induced the astrologically based variation for Intelligence. It is suggested, as much to knowledgeable as to no knowledgeable subjects, a factor of differenciated susceptibility to the outer world due the Cold-Hot scale. Are analysed the possible theoretical explanations and implications of these findings.
Byström, André. "Analys av solcellers påverkan pålågspänningsnätets elkvalitet." Thesis, Karlstads universitet, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-84937.
Повний текст джерелаAs Sweden moves towards a more climate-smart and sustainable society at the same time as the taxdeductions on solar cells become more profitable and less complicated, installations of solar cellshave undergone an enormous increase in recent years. A rate of increase that is expected tocontinue. If many customers choose to install large solar cells with high power in a weak area, thenthis could lead to problems in the form of voltage variations and overloads in the electricity grid. Thepurpose of the study is therefore to identify the areas where many solar installations can lead toproblems, investigate the factors that are risks for problematic networks, list and prioritize networksin need of measures. As well as to investigate in which areas large-scale installation of solar cells aremost likely to occur in.In the study, a broad analysis was performed of Ellevio's low voltage network, where voltagevariations and overloads in the network were investigated. Three areas from the analysis with lowpotential for solar cells were analyzed more deeply to check the condition of intermediate networks.Measurement data from areas with installed solar cells were processed to be used as a reference forwhat actual solar production can look like. To investigate where future solar cells can be installed,the spatial neighborhood effect and average income by postcode were studied. Finally, Ellevio'snetwork was listed and prioritized according to the need for measures, where the prioritization isbased on areas with the highest consequence and where future solar cells are most likely to arise.The result is a risk assessment where the proportion of areas is presented based on the probabilitythat solar cells arise and consequences. The analysis shows that the parameter that affected mostareas in the low-voltage network is voltage variation in the connection points. The in-depth analysisshows that intermediate networks are similar, if not more vulnerable to large-scale installation ofsolar cells. The areas with installed solar cells show that the individually highest produced powernever reaches the installed one and that the combined power for the solar producers in an area endsup far below the installed power.
Nguyen, Thai Chinh [Verfasser], Harald [Akademischer Betreuer] Schuh, Mahdi [Akademischer Betreuer] Alizadeh, Harald [Gutachter] Schuh, Mahdi [Gutachter] Alizadeh, and Lung-Chih [Gutachter] Tsai. "Use of the East Asia GPS receiving network to observe ionospheric VTEC variations, scintillation and EIA features during the Solar Cycle 24 / Thai Chinh Nguyen ; Gutachter: Harald Schuh, Mahdi Alizadeh, Lung-Chih Tsai ; Harald Schuh, Mahdi Alizadeh." Berlin : Technische Universität Berlin, 2021. http://d-nb.info/1231908394/34.
Повний текст джерелаAoun, Youva. "Evaluation de la sensibilité de l’instrument FCI à bord du nouveau satellite Meteosat Troisième Génération imageur (MTG-I) aux variations de la quantité d’aérosols d’origine désertique dans l’atmosphère." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM030/document.
Повний текст джерелаThis thesis deals with a methodology to assess the capabilities of future spaceborne instruments. The case study is the Flexible Combined Imager (FCI) of the future Meteosat Third Generation Imaging mission (MTG - I), and in particular its ability to detect variations in load of desert aerosols in a realistically variable atmosphere. A better understanding of the behavior of these aerosols is part of regularly expressed needs for the study of the climate, weather forecast or assessment of the solar resource in arid areas such as the Sahara. This type of aerosols is abundant in the atmosphere. Their physical and chemical properties make them distinguishable from other types of aerosols such as those resulting from anthropogenic pollution, especially as they are emitted in areas protected from contamination by these other types. They therefore represent a simple case study to validate the methodology developed in this thesis.The methodology is to provide a simulator of the view of the instrument to perform a large number of simulations of the radiance measured under different atmospheric conditions and ground albedo, to analyze the results in order to quantify the influence of each variable in the variation of radiance, and then conclude on the capabilities of detection through a test of detectability taking into account the characteristics of the instrument.The developed simulator was validated by comparison against actual measurements of the SEVIRI instruments onboard Meteosat Second Generation satellites. The main innovation lies in the use of the global sensitivity analysis approach (GSA). The latter quantifies the influence of each variable separately as well as their crossed terms. Cumulative distribution functions were computed from actual observations and allow a realistic sensitivity analysis of the instrument. The GSA is also used to compute functional representation of the influence of one or more variables on the variability of the observed signal. The usefulness of such representations is discussed for various applications in remote sensing
Chapman, Steven Anthony. "The variation of coronal holes with solar cycle." Thesis, University of Central Lancashire, 2007. http://clok.uclan.ac.uk/20984/.
Повний текст джерелаGuo, Huairui. "Variation monitoring, diagnosis and control for complex solar cell manufacturing processes." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280704.
Повний текст джерелаChapana, Randi Synnøve Hegdal. "The Relative Influence of Solar Radiative and Solar Geomagnetic Variation on the Dynamics of the Polar Upper Mesosphere." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18887.
Повний текст джерелаLas, Vergnas Olivier. "Contribution à l'étude des estimations historiques des éclats des étoiles brillantes par des analyses multidimensionnelles." Phd thesis, Université Pierre et Marie Curie - Paris VI, 1990. http://tel.archives-ouvertes.fr/tel-00655551.
Повний текст джерелаBrilliant, Debra. "A study of nitrogen isotopic systematics in lunar soils and breccias." Thesis, n.p, 1999. http://oro.open.ac.uk/19082/.
Повний текст джерелаHossain, Sonia. "Influence of Climatic Variation on Soybean Yield in Japan and Asia." Kyoto University, 2014. http://hdl.handle.net/2433/189680.
Повний текст джерела0048
新制・課程博士
博士(農学)
甲第18523号
農博第2080号
新制||農||1026(附属図書館)
学位論文||H26||N4867(農学部図書室)
31409
京都大学大学院農学研究科農学専攻
(主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也
学位規則第4条第1項該当
Soukharev, B. E., and L. L. Hood. "Solar cycle variation of stratospheric ozone: Multiple regression analysis of long-term satellite data sets and comparisons with models." AMER GEOPHYSICAL UNION, 2006. http://hdl.handle.net/10150/623340.
Повний текст джерелаHood, L. L. "The solar cycle variation of total ozone: Dynamical forcing in the lower stratosphere." AMER GEOPHYSICAL UNION, 1997. http://hdl.handle.net/10150/624010.
Повний текст джерелаUnderhill, Christopher John. "A characterisation of noise sources in BiSON data, and their variation over the solar cycle." Thesis, University of Birmingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549250.
Повний текст джерелаJones, S. L. "Negating the Yearly Eccentricity Magnitude Variation of Super-synchronous Disposal Orbits due to Solar Radiation Pressure." Thesis, University of Colorado at Boulder, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1539339.
Повний текст джерелаSolar radiation pressure alters satellites' eccentricity by accelerating and decelerating them during each orbit. The accumulated perturbation cancels yearly for geostationary satellites, but meanwhile the perigee radius changes. Disposed satellites must be reorbited higher to compensate, using more fuel. The examined disposal orbit points toward the Sun and uses the satellite's natural eccentricity. This causes the eccentricity vector to only change direction, keeping the perigee radius constant. This thesis verifies this behavior over one year with an analytical derivation and MATLAB simulation, gaining useful insights into its cause. The traditional and proposed disposal orbits are then modeled using NASA's GMAT for more realistic simulations. The proposed orbit's sensitivity to satellite and initialization errors is also examined. Relationships are developed to show these errors' effect on the perigee radius. In conclusion, while this orbit can be used in the short term, margins are necessary to guarantee protection of the geostationary belt.
Theys, Céline. "Détection et caractérisation de variations dans des signaux non stationnaires : application à des signaux SONAR." Nice, 1993. http://www.theses.fr/1993NICE4676.
Повний текст джерелаRogers, Hannah Mallalieu. "Labile Ligand Variation in Polyazine-Bridged Ruthenium/Rhodium Supramolecular Complexes Providing New Insight into Solar Hydrogen Production from Water." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/64364.
Повний текст джерелаPh. D.
Cook, Daniel A. "Variational and active surface techniques for acoustic and electromagnetic imaging." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53522.
Повний текст джерелаEppanapelli, Lavan Kumar. "Investigation of wind potential variation at three measurement sites based on atmospheric stability and power production." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-136935.
Повний текст джерелаTowfie, Nazley. "Dynamic variation of hydrogen dilution during hot-wire chemical vapour deposition of silicon thin films." Thesis, University of the Western Cape, 2013. http://hdl.handle.net/11394/3813.
Повний текст джерела>Magister Scientiae - MSc
Kübler, Svea. "Evaluation of the Variation in Operating Point for a Solar-Driven Gas-Yurbine and its Influence on the Performance of the Machine." Thesis, KTH, Energiteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-72489.
Повний текст джерелаDidelot, Aurélien. "Films d’oxydes de vanadium thermochromes dopés aluminium obtenus après un recuit d’oxydation-cristallisation pour applications dans le solaire thermique." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0307/document.
Повний текст джерелаThis work is a CIFRE thesis between VIESSMANN Faulquemont SAS society and the laboratory Institut Jean Lamour. In order to strongly reduce the problems associated with high stagnation temperature, we present a new generation of solar absorbent layers based on a smart thermochromic vanadium dioxide thin film. Vanadium dioxide (VO2) is a material which exhibit a metal insulator transition (MIT) at a critical temperature of 68°C (Tc). The transition is accompanied by a change in crystallographic structure VO2(M), while a rutile-like structure VO2(R) is obtained at high temperature. This structural change induces a drastic modification of the optical properties. The synthesis of vanadium-based films is performed using magnetron sputtering. We proceed to a subsequent annealing in air to form crystalline films of about 400 nm thickness. In order to increase the thermochromic effect of our thin film (Δε) we study the temperature and duration of the annealing. In a second time we try to increase the emissivity switch between the low and high temperature phase by adding an aluminum doping. After optimization, scale up have been successfully done and the optimized parameters have been used to build a prototype of thermochromic selective layer that has been compared to the standard industrial solar absorber
Tenholt, Frederik Josef [Verfasser], Julia [Gutachter] Tjus, and Horst [Gutachter] Fichtner. "Studying the temporal variation of the cosmic-ray sun shadow : comparison of IceCube data with models of the solar magnetic field / Frederik Tenholt ; Gutachter: Julia Tjus, Horst Fichtner ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1205976329/34.
Повний текст джерелаTenholt, Frederik [Verfasser], Julia [Gutachter] Tjus, and Horst [Gutachter] Fichtner. "Studying the temporal variation of the cosmic-ray sun shadow : comparison of IceCube data with models of the solar magnetic field / Frederik Tenholt ; Gutachter: Julia Tjus, Horst Fichtner ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1205976329/34.
Повний текст джерелаAntoine, Joseph. "Synthèse par pulvérisation cathodique de pérovskites thermochromes comme couche sélective "haute performance" d'absorbeurs solaires thermiques." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0273.
Повний текст джерелаThe present PhD work is focused on the study of the LaCoO3 system deposited as a thin film by reactive magnetron sputtering. The first part of this work is dedicated to the influence of the deposition parameters on the film structure. The influences of heat treatment parameters and deposition total pressure on the thermochromic transition are discussed. We have shown that it is possible to control the ratio between the cubic and rhombohedral phases as well as the size of the crystallites through the control of our parameters. In a second part, we studied in detail the properties changes using synchrotron radiation and transmission electron microscopy. Our measurements have shown that the cubic phase and the crystallites size influence the spin of cobalt atoms and therefore the nature of the Co-O bonds. We have shown that a fine microstructure and a rhombohedral phase increase the thermochromic effect and the optical switch of the transition thanks to an increase in the population density at the Fermi level and a decrease of the optical gap
Jovan, Bajčetić. "Modelovanje uticaja intenzivnih promena Sunčevog zračenja na prostiranje radio talasa." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2017. https://www.cris.uns.ac.rs/record.jsf?recordId=102468&source=NDLTD&language=en.
Повний текст джерелаThis thesis presents the research results of intensive solar radiation variationinfluence on radio propagation. The first part of presented results is related to theeffects of non-periodic radiation within X-ray wavelength during Solar X-flare.Modelling of ionosphere D-layer medium is performed during all time duration ofadditional ionization energy, as well as radio propagation characteristics within thismedium. The second part of the measured results presents periodic variation ofreceiving microwave radio signal level of experimental Line-of-site communicationduring the morning hours. It is shown that this variation is highly correlated withgeomagnetic field component values variation and that is caused by the Sunappearance on the horizon. Based on the experimentally collected results, the modelthat describes this variation during morning hours is proposed.
Juwono, Alamsyah M. "Cosmic ray solar diurnal and sidereal variations." Thesis, 1997. https://eprints.utas.edu.au/20379/1/whole_JuwonoAlamsyahM1997_thesis.pdf.
Повний текст джерелаShepherd, Simon J., S. I. Zharkov, and Valentina V. Zharkova. "Prediction of Solar Activity from Solar Background Magnetic Field Variations in Cycles 21-23." Thesis, 2014. http://hdl.handle.net/10454/10790.
Повний текст джерелаA comprehensive spectral analysis of both the solar background magnetic field (SBMF) in cycles 21-23 and the sunspot magnetic field in cycle 23 reported in our recent paper showed the presence of two principal components (PCs) of SBMF having opposite polarity, e. g., originating in the northern and southern hemispheres, respectively. Over a duration of one solar cycle, both waves are found to travel with an increasing phase shift toward the northern hemisphere in odd cycles 21 and 23 and to the southern hemisphere in even cycle 22. These waves were linked to solar dynamo waves assumed to form in different layers of the solar interior. In this paper, for the first time, the PCs of SBMF in cycles 21-23 are analyzed with the symbolic regression technique using Hamiltonian principles, allowing us to uncover the underlying mathematical laws governing these complex waves in the SBMF presented by PCs and to extrapolate these PCs to cycles 24-26. The PCs predicted for cycle 24 very closely fit (with an accuracy better than 98%) the PCs derived from the SBMF observations in this cycle. This approach also predicts a strong reduction of the SBMF in cycles 25 and 26 and, thus, a reduction of the resulting solar activity. This decrease is accompanied by an increasing phase shift between the two predicted PCs (magnetic waves) in cycle 25 leading to their full separation into the opposite hemispheres in cycle 26. The variations of the modulus summary of the two PCs in SBMF reveals a remarkable resemblance to the average number of sunspots in cycles 21-24 and to predictions of reduced sunspot numbers compared to cycle 24: 80% in cycle 25 and 40% in cycle 26.
Ho, Wan-chien, and 何萬謙. "Variations of ionospheric neutral densities in response to solar activity." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/71310393180035983666.
Повний текст джерела國立中央大學
太空科學研究所
102
This thesis focuses on the studies of variations of neutral densities at a height of 410 Km in response to solar activity. It use solar radiation indices F10.7 and EUV to linearly fit neutral density measured by the Challenging Minisatellite Payload (CHAMP) satelliteduring the period 2003 - 2008. Aclearly phase delay in solar radiation and neutral density have been found when we were doing data analysis. It's also pointed out that neutral density variation has a time delay with solar radiation in the previous papers. In this study, we could get a conclusion that the time delay is one day during 2003 to 2008. In doing the linear regression,the result from multiple parameters is almost the same as that from single parameter. And, because of the more completeness of the observations of F10.7 than EUV, we decide to use F10.7 index to be the main parameter in the following studies. To compare original data of neutral density with the fitted data has a significant difference in the period of low solar activity. The difference has high relation with Kp index. Additional linear regression is required for these differences with Kp index.The results indicate that solar radiation is a dominate factor in the variations of neutral densities in the period of high solar activity, and geomagnetic activity produced by the solar wind becomes important in the low solar activity. The difference between original data of neutral density with the fitted data has a period of 130 days, which can be attributed to the satellite orbit.Removement of this component can increase the correlation coefficient of the original data the fitted data up to 0.95. But this effect is only important in the period near solar minimum.
Zharkova, Valentina V., Simon J. Shepherd, E. Popova, and Sergei I. Zharkov. "Heartbeat of the Sun from Principal Component Analysis and prediction of solar activity on a millenium timescale." 2015. http://hdl.handle.net/10454/11803.
Повний текст джерелаWe derive two principal components (PCs) of temporal magnetic field variations over the solar cycles 21–24 from full disk magnetograms covering about 39% of data variance, with σ = 0.67. These PCs are attributed to two main magnetic waves travelling from the opposite hemispheres with close frequencies and increasing phase shift. Using symbolic regeression analysis we also derive mathematical formulae for these waves and calculate their summary curve which we show is linked to solar activity index. Extrapolation of the PCs backward for 800 years reveals the two 350-year grand cycles superimposed on 22 year-cycles with the features showing a remarkable resemblance to sunspot activity reported in the past including the Maunder and Dalton minimum. The summary curve calculated for the next millennium predicts further three grand cycles with the closest grand minimum occurring in the forthcoming cycles 26–27 with the two magnetic field waves separating into the opposite hemispheres leading to strongly reduced solar activity. These grand cycle variations are probed by α − Ω dynamo model with meridional circulation. Dynamo waves are found generated with close frequencies whose interaction leads to beating effects responsible for the grand cycles (350–400 years) superimposed on a standard 22 year cycle. This approach opens a new era in investigation and confident prediction of solar activity on a millenium timescale.
Gong, Bin. "Variations of Jovian aurora induced by changes in solar wind dynamic pressure." Thesis, 2005. http://hdl.handle.net/1911/18908.
Повний текст джерелаHuang, Guan-Han, and 黃冠瀚. "Constructing Solar Synoptic Maps to Study The Temporal Variations of Coronal Holes." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/09312845136150154268.
Повний текст джерела國立中央大學
太空科學研究所
104
Synoptic maps are approximations of the full surface of the sun. We construct synoptic maps from CR2099 to CR2158 to study the dark regions on the EUV image called coronal holes. The data are retrieved from Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager onboard Solar Dynamics Obervatory. Each synoptic map contains 48 central meridian images arranged in time series. Dark regions are extracted by the thresholding routines. A dark region is identified as a coronal hole if its magnetic field skewness exceeds 0.35. The sun is divided into north-polar (65° to 90°), mid-low latitude (-65° to 65°) and south-polar (-90° to -65°) region. Each region the area and unsigned flux of coronal holes are calculated and discussed. The result shows that mid-low latitude holes occupy 5% the area of mid-low latitude region, with unsigned flux 0.8×10^22 Mx. South-polar holes occupy 30% the area of the south polar region, with unsigned flux 0.4×10^22 Mx. Since south-polar region is much smaller than the mid-low latitude region, the magnetic field is stronger in south-polar holes than in mid-low latitude holes. In addition, we combine synoptic maps with Real-Time Solar Wind measurements on Advanced Composition Explorer, and try to trace fast solar wind particles from 1 AU back to the solar surface. The result shows that 48% of fast solar wind sources are close to the center of coronal holes.
Xu, Daoxiang, and 徐道翔. "A performance study of the cut solar cell base on shunt resistance variations." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/47405445508914458761.
Повний текст джерела聖約翰科技大學
電機工程系碩士班
100
This paper developed a detection method of cut solar cell. First using MATLAB software to simulate solar cell equivalent circuit mathematical model to understand the impact of solar cell equivalent circuit the shunt resistance change of the I-V curve. Established shunt resistance change will affect the slope of the curve near the short-circuit current in the I-V curve. On this basis, design level slope curve test method and reverse voltage test method, respectively use the solar cells irradiated (level curve slope test method) and unirradiated (reverse voltage test method) the shunt resistance characteristics, to achieve detection of cut solar cell performance. Finally comparison of measurement results and make recommendations.