相关论文: Empirical estimate of p-mode frequency shift for s…

We examine the solar-cycle variation of the power in the low-degree helioseismic modes by looking at binned power spectra from 45 years of observations with the Birmingham Solar Oscillations Network, which provides a more robust estimate of…

We study the sunspot activity in relation to spotless days (SLDs) during the descending phase of solar cycle $11$--$24$ to predict the amplitude of sunspot cycle $25$. For this purpose, in addition to SLD, we also use the geomagnetic…

The Sun's polar magnetic fields change their polarity near the maximum of sunspot activity. We analyzed the polarity reversal epochs in Solar Cycles 21 to 24. There was a triple reversal in the N-hemisphere in Solar Cycle 24 and single…

Context. Large-scale equatorial Rossby modes have been observed on the Sun over the last two solar cycles. Aims. We investigate the impact of the time-varying zonal flows on the frequencies of Rossby modes. Methods. A first-order…

We explore the sensitivity of the frequencies of low-degree solar p-modes to near-surface magnetic flux on different spatial scales and strengths, specifically to active regions with strong magnetic fields and ephemeral regions with weak…

Solar variability occurs over a broad range of spatial and temporal scales, from the Sun's brightening over its lifetime to the fluctuations commonly associated with magnetic activity over minutes to years. The latter activity includes most…

The presence of intense magnetic fields in and around sunspots is expected to modify the solar structure and oscillation frequencies. Applying the ring diagram technique to data from the Michelson Doppler Imager (MDI) on board the Solar and…

The short-term periodicities of the daily sunspot area fluctuations from August 1923 to October 1933 are discussed. For these data the correlative analysis indicates negative correlation for the periodicity of about 155 days, but the power…

Solar activities have a great impact on modern high-tech systems, such as human aerospace, satellite communication and navigation, deep space exploration, and related scientific research. Therefore, studying the long - term evolution trend…

Sunspot activity is highly variable and challenging to forecast. Yet forecasts are important, since peak activity has profound effects on major geophysical phenomena including space weather (satellite drag, telecommunications outages) and…

We investigated the solar cycle dependency on the presence and periodicity of the Quasi-Biennial Oscillation (QBO). Using helioseismic techniques, we used solar oscillation frequencies from the Global Oscillations Network Group (GONG),…

The use of different solar activity indices like sunspot numbers, sunspot areas, flare index, magnetic fields, etc., allows us to investigate the time evolution of some specific features of the solar activity and the underlying dynamo…

The minimum - maximum method, belonging to the precursor class of the solar activity forecasting methods, is based on a linear relationship between relative sunspot number in the minimum and maximum epochs of solar cycles. In the present…

The success of helioseismology is due to its capability to accurately measure the p-mode parameters of the solar eigenmode spectrum, which allow us to infer unique information about the internal structure and dynamics of the Sun. It also…

We describe systematic changes in the centroid frequencies and the splitting coefficients as found using data from MDI on board SOHO, covering cycle 23. The data allow us to construct a seismic map of the evolving solar activity -- covering…

In this paper, we aim to develop a predictive model for solar radial $p$-mode line profiles in the velocity spectrum. Unlike the approach favoured by prior studies, this model is not described by free parameters and we do not use fitting…

Accurate determination of the rotation rate in the radiative zone of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. We present here inferences…

The data of sunspot numbers, sunspot areas and solar flare index during cycle 23 are analyzed to investigate the intermediate-term periodicities. Power spectral analysis has been performed separately for the data of the whole disk, northern…

The recent paucity of sunspots and the delay in the expected start of Solar Cycle 24 have drawn attention to the challenges involved in predicting solar activity. Traditional models of the solar cycle usually require information about the…

We used the m-averaged spectrum technique ("collapsogram") to extract the low-frequency solar p-mode parameters of low- and intermediate-angular degrees (l \leq 35) in long time series of GONG and MDI observations. Rotational splittings and…