On mid-term periodicities of high-latitude solar activity

Deng, Linhua; Li, B.; Xiang, Yanjuan; Dun, G. T.

doi:10.1016/j.asr.2014.03.006

Cited by 37 publications

(11 citation statements)

References 36 publications

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“…This time-frequency analysis method was first proposed by Huang et al (1998) and has been applied in many research fields. For solar physics studies, Li et al (2012a) applied it to decompose the solar constant into three components: the rotation signal, the annual-variation, and the inter-solar-cycle signal; to study the periodic components of polar faculae and coronal green line intensity, Deng et al (2014) and Deng et al (2015) used the EMD to reveal the long-term temporal variation of solar time series; Xiang & Qu (2016) used it to extract the intrinsic mode functions (IMFs) of the solar mean magnetic field observed at the The EMD is usually applied to decompose a signal x(t) into a series of mono-component contributions designated as IMF and a secular trend (or a constant), namely:…”

Section: Ensemble Empirical Mode Decompositionmentioning

confidence: 99%

Periodic variation and phase analysis of grouped solar flare with sunspot activity

Deng

Mei

Wang

2020

Res. Astron. Astrophys.

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Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycle. Here we report the statistical analysis of grouped solar flare (GSF) and sunspot number (SN) during the time interval from January 1965 to March 2009. We find that, 1) the significant periodicities of both GSF and SN are related to the differential rotation periodicity, the quasi-biennial oscillation (QBO), and the eleven-year Schwabe cycle (ESC), but the specific values are not absolutely identical; 2) the ESC signal of GSF lags behind that of SN with an average of 7.8 months during the considered time interval, implying that the systematic phase delays between GSF and SN originate from the inter-solar-cycle signal. Our results may provide evidence about the storage of magnetic energy in the corona.

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Section: Ensemble Empirical Mode Decompositionmentioning

confidence: 99%

Periodic variation and phase analysis of grouped solar flare with sunspot activity

Deng

Mei

Wang

2020

Res. Astron. Astrophys.

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“…The key idea of HHT analysis is a combination of the empirical mode decomposition (EMD) to generate the intrinsic mode functions (IMFs) and the subsequent Hilbert spectral analysis (HAS) to identify the periodicities of extracted IMFs (Deng et al 2014).…”

Section: Hilbert-huang Transformmentioning

confidence: 99%

On midrange periodicities in solar radio flux and sunspot areas

Mei

Deng

Wang

2018

Astrophys Space Sci

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Using the Hilbert-Huang transform technique, we investigate the midrange periodicities in solar radio flux at 2800 MHz (F10.7) and sunspot areas (SAs) from February 1, 1947 to September 30, 2016. The following prominent results are found: (1) The quasiperiodic oscillations of both data sets are not identical, such as the rotational cycle, the midrange periodicities, and the Schwabe cycle. In particular, the midrange periodicities ranging from 37.9 days to 297.3 days are related to the magnetic Rossby-type waves; 2) The 1.3year and 1.7-year fluctuations in solar activity indicators are surface manifestations (from photosphere to corona) of magnetic flux changes generated deep inside the Sun; 3) At the timescale of the Schwabe cycle, the complicated phase relationships in the three intervals (1947-1958, 1959-1988, and 1989-2016) agree with the produced periodicities of the magnetic Rossbytype waves. The findings indicate that the magnetic Rossby-type waves are the possible physical mechanism behind the midrange periodicities of solar activity indicators. Moreover, the significant change in the relationship between photospheric and coronal activity took place after the maximum of solar cycle 22 could be interpreted by the magnetic Rossby-type waves.

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“…Pap [8] and Pap et al [9] found a 23.5-day period in solar irradiance. During solar cycles 19-24, various fluctuations with "mid-range" periods have been detected by authors in different phases of different solar cycles, such as 51, 62, 73, 152, and 546-day [10][11][12]. A type of oscillation with periods of around two years, which have been named qusi-biennial oscillations (QBOs) of the Sun, have also been found in many indicators, and have been paid increasing attention by authors in recent decades [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Periodic Variations of Solar Corona Index during 1939–2020

Tang

et al. 2022

Universe

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Periodic behaviors of solar magnetic indicators might provide a clue for the understanding of solar dynamic processes. Combining with a Lomb–Scargle periodogram, the concentration of frequency and time via a multitapered synchrosqueezed transform is applied to investigate the periodic variations of modified coronal index for the time interval from 1 January 1939 to 31 August 2020. The main results are as follows: (1) During solar cycles 19 to 23, the Schwabe cycle of the modified coronal index is operating with its length variating between 10.5 and 11-yr, and the average value of length is 10.67-yr with standard deviation of 0.14-yr. (2) The Rieger-type periods are mainly distributed in a range from 120 to 200 days. In addition, the periods vary somewhat intermittently during cycles 18 to 24, which are operating with the highest power in cycles 21 and 22 while the power is much lower in cycles 23 and 24. (3) For rotation periods, the temporal variation exhibits a highly intermittent pattern as an asymmetrical distribution with its 25th, 50th, and 75th quantile of 26, 27.8, and 31-day, respectively. (4) Other mid-range periods are also detected with an average period length of 8.07, 5.44, 3.42, 2.3, and 1.01-yr.

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On mid-term periodicities of high-latitude solar activity

Cited by 37 publications

References 36 publications

Periodic variation and phase analysis of grouped solar flare with sunspot activity

Periodic variation and phase analysis of grouped solar flare with sunspot activity

On midrange periodicities in solar radio flux and sunspot areas

Periodic Variations of Solar Corona Index during 1939–2020

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