Article
Astronomy & Astrophysics
Aleix Espuna Fontcuberta, Anubhab Ghosh, Saikat Chatterjee, Dhrubaditya Mitra, Dibyendu Nandy
Summary: The Sun's activity, associated with the solar magnetic cycle, creates space weather which can disrupt technologies. Predicting the solar magnetic cycle is important for humanity. Machine-learning algorithms, especially Echo State Network (ESN), show promising results for solar-cycle forecasting.
Article
Astronomy & Astrophysics
Inigo Arregui
Summary: This paper presents a new method for predicting solar cycles using Bayesian inference to calculate the probability of the maximum amplitude. The method quantifies the impact of uncertainty and provides an assessment of the prediction quality.
Article
Astronomy & Astrophysics
Peng-Xin Gao
Summary: Based on the Debrecen Photoheliographic Data (DPD) sunspot catalog, the cyclical behaviors of tilt angles of all sunspot groups (SGs) and SGs with angular separation constraint S > 2.5(?) in Solar Cycles (SCs) 21 - 23 are investigated. It is found that during SC 23, the cyclical behaviors of tilt angles are different from those of SCs 21 and 22. The findings indicate that the tilt angles of SGs show different patterns during different solar cycles, and their values depend on the phase of each cycle.
Article
Astronomy & Astrophysics
Bibhuti Kumar Jha, Aditya Priyadarshi, Sudip Mandal, Subhamoy Chatterjee, Dipankar Banerjee
Summary: The study analyzes the solar rotation profile using data from Kodaikanal Solar Observatory and finds that larger sunspots rotate slower than smaller ones. There was no variation in rotation rates between solar activity extremes (maxima and minima) observed in the analysis.
Article
Astronomy & Astrophysics
V. M. S. Carrasco, A. A. Pevtsov, J. M. Nogales, J. M. Vaquero
Summary: The complete dataset of sunspot drawings recorded at Sacramento Peak Observatory has been digitized, showing similar behavior to the International Sunspot Number with a relatively stable ratio observed during a specific period. This work marks the first step towards publishing the sunspot catalogue in digital format, with plans to include more information in future versions.
Article
Astronomy & Astrophysics
Sergio Bernabe, Gabriel Garcia, Victor M. S. Carrasco, Jose M. Vaquero
Summary: SunMap is a new open-source software designed to provide a free, simple, and versatile tool for scientists studying solar activity to generate solar synoptic maps.
Article
Astronomy & Astrophysics
Ilya Usoskin, Gennady Kovaltsov, Wilma Kiviaho
Summary: The Waldmeier rule remains robust across different sunspot (group) series, while the Gnevyshev-Ohl rule is stable for Solar Cycles 8 - 21 but becomes unstable before the Dalton minimum.
Review
Astronomy & Astrophysics
Prantika Bhowmik, Jie Jiang, Lisa Upton, Alexandre Lemerle, Dibyendu Nandy
Summary: The dynamic activity of stars, such as the Sun, affects planetary space environments through various factors. Solar phenomena like flares and coronal mass ejections can cause hazardous space weather. The primary driver of solar activity is magnetic fields created by a mechanism called the magnetohydrodynamic dynamo. While the mechanism of solar cycles has been studied for a long time, predicting the strength of future sunspot cycles remains challenging. This review discusses observational constraints, recent physical insights, and advances in solar cycle predictions.
SPACE SCIENCE REVIEWS
(2023)
Article
Astronomy & Astrophysics
Luis Leuzzi, Laura A. Balmaceda, Carlos Francile
Summary: Sunspot areas are crucial indices for solar activity, and combining data from different observatories requires careful calibration. This study compares daily and group values of sunspot areas from the SOON network, finding significant differences among stations but reliable calibration factors for daily values. The research also estimates irradiance deficit due to sunspots, with up to 150 ppm differences during peak solar activity, primarily from sunspot groups near the center of the solar disk.
Article
Astronomy & Astrophysics
R. J. Booth
Summary: This paper replicates and enhances the method used by Leamon et al. to predict the terminator of solar cycles, but finds that their claim to have identified a mathematically robust signature of terminators in sunspot records is not well founded. The results are significantly sensitive to both the starting point of the data and the centralizing constant used to provide a meaningful Hilbert phase. Realistic parameter choices may push the predicted terminator back by about 2 years, which has implications for predictions of the magnitude of the next cycle.
Article
Astronomy & Astrophysics
Peng-Xin Gao, Jing-Lan Xie
Summary: In this study, the importance of the collision of different magnetic systems in generating magnetically complex sunspot groups and major flares is investigated. The ALW index, representing the ratio of the area to the latitudinal width of sunspot groups, is defined. The research findings show the relationship between the percentage of complex sunspot groups and the ALW index, as well as the percentage of major flares.
Article
Engineering, Aerospace
Esraa Zeki Mohammed, Hussain Salih Akbar, Saaduldeen Husain Shukri
Summary: Recording solar activity is crucial in understanding space weather. This study monitored and recorded sunspot data in Baghdad, Iraq for cycles 22, 23, and 24. The results were compared to international studies, confirming the reliability of the local records.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Astronomy & Astrophysics
A. J. P. Aparicio, V. M. S. Carrasco, J. M. Vaquero
Summary: In this work, the maximum amplitude of Solar Cycle 25 is predicted using the 13-month smoothed SILSO Sunspot Number (version 2) as a predictor for the slope of the inflection point during the ascending part of the cycle. The predicted value obtained is 131 ± 32. Finally, the result is discussed in the context of the ongoing debate on solar activity prediction and compared with other predictions for Solar Cycle 25 obtained by different methods.
Article
Astronomy & Astrophysics
Egor Illarionov, Rainer Arlt
Summary: Catalogs from the Zurich Observatory contain positional information on sunspots, prominences, and faculae during the late 19th and early 20th centuries. By training a neural network model, we have reconstructed the coordinates and connected earlier observations with later programs. This database complements the sunspot-group catalogs of the Royal Greenwich Observatory and could inspire the processing of a large amount of astronomical data that is still in non-digitized or scanned image form.
Article
Astronomy & Astrophysics
Michal Svanda, Martina Pavelkova, Jiri Dvorak, Bozena Solarova
Summary: The relative number of sunspots is an important indicator for describing solar activity and has wide applications in solar physics and climate research. This study proposes a new iterative algorithm that optimally combines series obtained by multiple observers to construct a representative target series of relative sunspot number. Results show that the methodology provides comparable results with recent reconstructions of sunspot number. It also accounts for possible non-solar changes in observers' time series and provides reconstruction uncertainties.
