Results 21 to 30 of about 1,543 (284)
Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles [PDF]
Annales Geophysicae, 1994 Monthly averages of the Helsinki Ak-values have been reduced to the equivalent aa-indices to extend the aa-data set back to 1844. A periodicity of about five cycles was found for the correlation coefficient (r) between geomagnetic indices and sunspot ...
V. Mussino +3 more
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Does Correction Factor Vary with Solar Cycle? [PDF]
Journal of Astronomy and Space Sciences, 2012 Monitoring sunspots consistently is the most basic step required to study various aspects of solar activity. To achieve this goal, the observers must regularly calculate their own correction factor k and keep it stable. Relatively recently, two observing
Heon-Young Chang, Sung-Jin Oh
doaj +1 more source
Forecasting sunspot numbers with Feedforward Neural Networks (FNN) using 'sunspot neural forecaster' system [PDF]
, 2011 This paper presents the investigations of forecasting performance of different type of Feedforward Neural Networks (FNN) in forecasting the sunspot numbers.
Reza Ezuan, Samin +4 more
core +1 more source
Periodic analysis of forest fire numbers and sunspot numbers in Türkiye
, 2022 The aim of this study is to examine the periodic structures of forest fire numbers in Türkiye and sunspot numbers. The main purpose of this study is to investigate the variability of forest fire numbers in Turkey and sunspot numbers using continuous ...
Cengiz, Taner Mustafa +1 more
core +1 more source
, 2022 Iterative code for computation of sunspot numbersIf you use this software, please cite it as ...
Svanda, Michal
core +1 more source
Recalibration of the Sunspot-Number: Status Report
Solar Physics, 2023 AbstractWe report progress on the ongoing recalibration of the Wolf sunspot number ($S_{\mathrm{N}}$SN) and group-sunspot number ($G_{\mathrm{N}}$GN) following the release of version 2.0 of$S_{\mathrm{N}}$SNin 2015. This report constitutes both an update of the efforts reported in the 2016 Topical Issue of Solar Physics and a summary of work by the ...
Clette, F. +20 more
openaire +5 more sources
A Unified Shape Model For Sunspot Number Cycles
Ratio Mathematica, 2021 Modelling and prediction of sunspot number time series is an unavoidable activity in the space object re-entry prediction community. Different mathematical functions have been proposed in the literature as sunspot number cycle model, since the McNish ...
GP Beena, A Sabarinath, AK Anilkumar
doaj +1 more source
HEMISPHERIC SUNSPOT UNIT AREA: COMPARISON WITH HEMISPHERIC SUNSPOT NUMBER AND SUNSPOT AREA
The Astronomical Journal, 2014 The monthly mean northern and southern hemispheric sunspot numbers (SNs) and sunspot areas (SAs) in the time interval of 1945 January to 2012 December are utilized to construct the monthly northern and southern hemispheric sunspot unit areas (SUAs), which are defined as the ratio of hemispheric SA to SN.
K. J. Li +3 more
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Change of Sunspot Groups Observed from 2002 to 2011 at ButterStar Observatory [PDF]
Journal of Astronomy and Space Sciences, 2012 Since the development of surface magnetic features should reflect the evolution of the solar magnetic field in the deep interior of the Sun, it is crucial to study properties of sunspots and sunspot groups to understand the physical processes working ...
Sung-Jin Oh, Heon-Young Chang
doaj +1 more source
TWO REGIMES IN THE REGULARITY OF SUNSPOT NUMBER
The Astrophysical Journal, 2013 Sunspot numbers WN display quasi-periodical variations that undergo regime changes. These irregularities could indicate a chaotic system and be measured by Lyapunov exponents. We define a functional λ (an "irregularity index") that is close to the (maximal) Lyapunov exponent for dynamical systems and well defined for series with a random component ...
Shapoval, A. +3 more
openaire +1 more source