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Relevant bibliographies by topics / Sunspot activity / Dissertations / Theses

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Dissertations / Theses on the topic 'Sunspot activity'

Author: Grafiati

Published: 5 June 2025

Last updated: 2 August 2025

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1

Takizawa, Kan. "Evolution and Flare Activity of δ-spots in Cycle 23". 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/202793.

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Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(理学)<br>甲第19359号<br>理博第4121号<br>新制||理||1593(附属図書館)<br>32373<br>新制||理||1593<br>京都大学大学院理学研究科物理学・宇宙物理学専攻<br>(主査)教授一本潔, 教授柴田一成, 准教授野上大作<br>学位規則第4条第1項該当

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2

Yousef, Mohammed A. "Astrostatistics: Statistical Analysis of Solar Activity from 1939 to 2008." Bowling Green State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1395405508.

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3

JABBARI, SARAH. "Origin of solar surface activity and sunspots." Licentiate thesis, Stockholms universitet, Institutionen för astronomi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-103637.

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In the last few years, there has been significant progress in the development of a new model for explaining magnetic flux concentrations, by invoking the negative effective magnetic pressure instability (NEMPI) in a highly stratified turbulent plasma. According to this model, the suppression of the turbulent pressure by a large-scale magnetic field leads to a negative contribution of turbulence to the effective magnetic pressure (the sum of non-turbulent and turbulent contributions). For large magnetic Reynolds numbers the negative turbulence contribution is large enough, so that the effective

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4

Valliappan, Senthamizh Pavai [Verfasser], and Carsten [Akademischer Betreuer] Denker. "Solar Activity Reconstruction from Historical Observations of Sunspots / Senthamizh Pavai Valliappan ; Betreuer: Carsten Denker." Potsdam : Universität Potsdam, 2018. http://d-nb.info/1218403764/34.

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5

Ishak, Muhammad Izzuddin Syakir. "A Reconnaissance Study of Water and Carbon Fluxes in Tropical Watersheds of Peninsular Malaysia: Stable Isotope Constraints." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30564.

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Evapotranspiration is a nexus for planetary energy and carbon cycles, as yet poorly constrained. Here I use stable isotopes of oxygen and hydrogen to partition flux of water due to plant transpiration from the direct evaporative flux from soils, water bodies and plant. The study areas, Langat and Kelantan watersheds represent examples of domains dominated by the respective Southwest and Northeast monsoons on the two sides of the main orographic barrier (Titiwangsa mountain range). Mean annual rainfall for the Langat watershed, obtained from 30 years of hydrological data, is 2145 ± 237 mm. Tent

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6

Hansson, Anton. "Solar Cycles and the Accuracy and Precision of GNSS Measurements." Thesis, KTH, Geodesi och geoinformatik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-132304.

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Today, GNSS (Global Navigation Satellite Systems) is a widely spread technology and are used in many different ways. GNSS is the collective name for American GPS, Russian Glonass and European Galileo and some other smaller navigation systems. When surveying with GNSS technology, there are many things that can affect the accuracy of the measurements. In this thesis the focus is on how these measurements are being effected by disturbances in the ionosphere. The conditions in the ionosphere are largely affected by the amount of solar activities. A guideline for the amount of solar activity is to

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7

Zhang, L. (Liyun). "Solar active longitudes and their rotation." Doctoral thesis, University of Oulu, 2013. http://urn.fi/urn:isbn:9789526200262.

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Abstract In this thesis solar active longitudes of X-ray flares and sunspots are studied. The fact that solar activity does not occur uniformly at all heliographic longitudes was noticed by Carrington as early as in 1843. The longitude ranges where solar activity occurs preferentially are called active longitudes. Active longitudes have been found in various manifestations of solar activity, such as sunspots, flares, radio emission bursts, surface and heliospheric magnetic fields, and coronal emissions. However, the active longitudes found when using different rigidly rotating reference frames

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8

Amabayo, Emirant Bertillas. "Multi-instrument observations of ionospheric irregularities over South Africa." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005261.

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The occurrence of mid-latitude spread F (SF) over South Africa has not been extensively studied since the installation of the DPS-4 digisondes at Madimbo (30.88◦E, 22.38◦S), Grahamstown (33.32◦S, 26.50◦E) and Louisvale (28.51◦S, 21.24◦E). This study is intended to quantify the probability of the occurrence of F region disturbances associated with ionospheric spread F (SF) and L-band scintillation over South Africa. This study used available ionosonde data for 8 years (2000-2008) from the three South African stations. The SF events were identified manually on ionograms and grouped for further s

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9

Colak, Tufan, and Rami S. R. Qahwaji. "Automated Solar Activity Prediction: A hybrid computer platform using machine learning and solar imaging for automated prediction of solar flares." AGU, 2009. http://hdl.handle.net/10454/4106.

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yes<br>The importance of real-time processing of solar data especially for space weather applications is increasing continuously. In this paper, we present an automated hybrid computer platform for the short-term prediction of significant solar flares using SOHO/Michelson Doppler Imager images. This platform is called the Automated Solar Activity Prediction tool (ASAP). This system integrates image processing and machine learning to deliver these predictions. A machine learning-based system is designed to analyze years of sunspot and flare data to create associations that can be represented us

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10

Zharkova, Valentina V., J. Aboudarham, Sergei I. Zharkov, Stanley S. Ipson, Ali K. Benkhalil, and N. Fuller. "Solar Feature Catalogues in EGSO." Springer, 2005. http://hdl.handle.net/10454/4032.

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no<br>The Solar Feature Catalogues (SFCs) are created from digitized solar images using automated pattern recognition techniques developed in the European Grid of Solar Observation (EGSO) project. The techniques were applied for detection of sunspots, active regions and filaments in the automatically standardized full-disk solar images in Caii K1, Caii K3 and H¿ taken at the Meudon Observatory and white-light images and magnetograms from SOHO/MDI. The results of automated recognition are verified with the manual synoptic maps and available statistical data from other observatories that reveale

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11

Haywood, Raphaëlle D. "Hide and seek : radial-velocity searches for planets around active stars." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7798.

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The detection of low-mass extra-solar planets through radial-velocity searches is currently limited by the intrinsic magnetic activity of the host stars. The correlated noise that arises from their natural radial-velocity variability can easily mimic or conceal the orbital signals of super-Earth and Earth-mass extra-solar planets. I developed an intuitive and robust data analysis framework in which the activity-induced variations are modelled with a Gaussian process that has the frequency structure of the photometric variations of the star, thus allowing me to determine precise and reliable pl

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12

Ashamari, Omar, Rami S. R. Qahwaji, Stanley S. Ispon, M. Schöll, O. Nibouche, and M. Haberreiter. "Identification of photospheric activity features from SOHO/MDI data using the ASAP tool." 2015. http://hdl.handle.net/10454/7580.

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Yes<br>The variation of solar irradiance is one of the natural forcing mechanisms of the terrestrial climate. Hence, the time-dependent solar irradiance is an important input parameter for climate modelling. The solar surface magnetic field is a powerful proxy for solar irradiance reconstruction. The analyses of data obtained with the Michelson Doppler Imager (MDI) on board the SOHO mission are therefore useful for the identification of solar surface magnetic features to be used in solar irradiance reconstruction models. However, there is still a need for automated technologies that would

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13

Wu, Chi-Ju. "Solar Variability over the Last 9000 Years." Doctoral thesis, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E494-6.

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14

Jabbari, Sarah. "Origin of solar surface activity and sunspots." Doctoral thesis, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-128774.

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Sunspots and active regions are two of the many manifestations of the solar magnetic field. This field plays an important role in causing phenomena such as coronal mass ejections, flares, and coronal heating. Therefore, it is important to study the origin of sunspots and active regions and determine the underlying mechanism which creates them. It is believed that flux tubes rising from the bottom of the convection zone can create sunspots. However, there are still unanswered questions about this model. In particular, flux tubes are expected to expand as they rise, hence their strength weakens

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15

Shepherd, 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.

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yes<br>A 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 t

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16

St-Laurent-Lemerle, Alexandre. "Modélisation hybride du cycle d’activité solaire : évolution couplée du flux magnétique photosphérique et de la dynamo interne." Thèse, 2017. http://hdl.handle.net/1866/20769.

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17

Park, S. H., K. D. Leka, K. Kusano, et al. "A Comparison of Flare Forecasting Methods. IV. Evaluating Consecutive-day Forecasting Patterns." 2019. http://hdl.handle.net/10454/18411.

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No<br>A crucial challenge to successful flare prediction is forecasting periods that transition between "flare-quiet" and "flare-active." Building on earlier studies in this series in which we describe the methodology, details, and results of flare forecasting comparison efforts, we focus here on patterns of forecast outcomes (success and failure) over multiday periods. A novel analysis is developed to evaluate forecasting success in the context of catching the first event of flare-active periods and, conversely, correctly predicting declining flare activity. We demonstrate these evaluation me

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