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Related papers: A model-free, data-based forecast for sunspot cycl…

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We present a comprehensive analysis of Solar Cycle 25 aimed at precisely constraining the interval of its activity maximum using multiple observational parameters: sunspot number (SSN), Wolf number, the 10.7 cm solar radio flux (F10.7), the…

Solar and Stellar Astrophysics · Physics 2025-11-24 Homer Dávila Gutiérrez

Solar polar fields are essential for the solar cycle and the heliospheric magnetic field. Cycle 25 is now entering its declining phase, the critical period during which most of the cycle's polar fields are established. Therefore, reliable…

Solar and Stellar Astrophysics · Physics 2026-03-31 Ruihui Wang , Jie Jiang , Yukun Luo

It has recently been discovered that the time phases (time-varying delays) of the irregular periodicities observed in the Sunspot series, consisting of the approximate 27-day latitude-averaged plasma rotation and approximate 11-yr magnetic…

Solar and Stellar Astrophysics · Physics 2026-02-24 William A. Gardner , Antonio Napolitano

The magnetic cycle of the Sun, as manifested in the cyclic appearance of sunspots, significantly influences our space environment and space-based technologies by generating what is now termed as space weather. Long-term variation in the…

Solar and Stellar Astrophysics · Physics 2011-10-27 Dibyendu Nandy

Total solar irradiance variations, about 0.1% between solar activity maximum and minimum, are available from accurate satellite measurements since 1978 and thus do not provide useful information on longer-term secular trends. Recently,…

Solar and Stellar Astrophysics · Physics 2012-05-23 S. Sello

The sunspot number data during the past 400 years indicates that both the profile and the amplitude of the solar cycle have large variations. Some precursors of the solar cycle were identified aiming to predict the solar cycle. The polar…

Solar and Stellar Astrophysics · Physics 2015-06-15 Jie Jiang

The mainstream dynamo models predict that the sunspot cycle is non-stationary and stochastic. The official Solar Cycle Prediction Panel forecasts only the ongoing sunspot cycle because any forecast beyond one cycle is considered impossible.…

Solar and Stellar Astrophysics · Physics 2025-08-14 Lauri Jetsu

The long term study of the Sun is necessary if we are to determine the evolution of sunspot properties and thereby inform modeling of the solar dynamo, particularly on scales of a solar cycle. We aim to determine a number of sunspot…

Solar and Stellar Astrophysics · Physics 2011-08-23 Fraser T. Watson , Lyndsay Fletcher , Stephen Marshall

Further development of the work of Obridko et al. [1] based on recent data confirms the assumption that the 25th cycle of solar activity is a medium-low cycle. Its height is expected to be $125.2\pm5.6$, and the expected date of the maximum…

Solar and Stellar Astrophysics · Physics 2023-07-13 V. N. Obridko , D. D. Sokoloff , M. M. Katsova

The maximum of a solar cycle contain two or more peaks, known as Gnevyshev peaks. Studies of this property of solar cycles may help for better understanding the solar dynamo mechanism. We analysed the 13-month smoothed monthly mean…

Solar and Stellar Astrophysics · Physics 2023-02-27 J. Javaraiah

Recent research has demonstrated the existence of a new type of solar event, the "terminator." Unlike the Sun's signature events, flares and Coronal Mass Ejections, the terminator most likely originates in the solar interior, at or near the…

Solar and Stellar Astrophysics · Physics 2020-03-11 Robert J Leamon , Scott W. McIntosh , Sandra C. Chapman , Nicholas W. Watkins

A new formula for predicting solar cycles based on the current theoretical understanding of the solar cycle from flux transport dynamo is presented. Two important processes---fluctuations in the Babcock-Leighton mechanism and variations in…

Solar and Stellar Astrophysics · Physics 2019-08-07 Gopal Hazra , Arnab Rai Choudhuri

Surface flux transport simulations for the descending phase of cycle 24 using random sources (emerging bipolar magnetic regions) with empirically determined scatter of their properties provide a prediction of the axial dipole moment during…

Solar and Stellar Astrophysics · Physics 2016-06-01 Robert H. Cameron , Jie Jiang , Manfred Schuessler

We present the assessment of a diffusion-dominated mean field axisymmetric dynamo model in reproducing historical solar activity and forecast for solar cycle 25. Previous studies point to the Sun's polar magnetic field as an important proxy…

Solar and Stellar Astrophysics · Physics 2018-06-29 Alejandro Macario-Rojas , Katharine L. Smith , Peter C. E. Roberts

Forecasting the strength of the sunspot cycle is highly important for many space weather applications. Our previous studies have shown the importance of sunspot number variability in the declining phase of the current 11-year sunspot cycle…

Solar and Stellar Astrophysics · Physics 2017-12-18 Tatiana Podladchikova , Ronald Van der Linden , Astrid M. Veronig

One prominent feature of solar cycle is its irregular variation in its cycle strength, making it challenging to predict the amplitude of the next cycle. Studies show that fluctuations and nonlinearity in generating poloidal field throughout…

Solar and Stellar Astrophysics · Physics 2025-11-10 Bidisha Dey , Anu Sreedevi , Bidya Binay Karak

Despite the known general properties of the solar cycles, a reliable forecast of the 11-year sunspot number variations is still a problem. The difficulties are caused by the apparent chaotic behavior of the sunspot numbers from cycle to…

Astrophysics · Physics 2009-11-13 I. N. Kitiashvili , A. G. Kosovichev

The problem of prediction of a given time series is examined on the basis of recent nonlinear dynamics theories. Particular attention is devoted to forecast the amplitude and phase of one of the most common solar indicator activity, the…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Stefano Sello

The main purpose of this study is the determination of solar minimum date of the new sunspot cycle No 24. It is provided by using of four types of mean daily data values for the period Jan 01. 2006 - Dec 31. 2009: (1) the solar radioindex…

Solar and Stellar Astrophysics · Physics 2010-08-03 B. Komitov , P. Duchlev , K. Stoychev , M. Dechev , K. Koleva

The forthcoming solar cycle (SC) 25 was beleived to be rather low when using the sunspot number (SN) as a measurement of the level of activity. The most popular prediction was made by the panel of NASA in 2019, including works based on…

Solar and Stellar Astrophysics · Physics 2022-05-19 S. Koutchmy , B. Filippov , E. Tavabi , J-C. Noens , O. Wurmser