On midrange periodicities in solar radio flux and sunspot areas

Abstract

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.

A long term multi-frequency study of solar rotation using solar radio flux and its relationship with solar cycles

“…The smoothness of curve, in some cases, is affected by the presence of gap of data of some year's. So we can conclude, that when shorter duration components (less than 3 year) are suppressed than the periodic components of ∼11 yrs, which are also embedded in the analyzed rotation period data and their presence is perhaps due to the 11 yrs sunspot activity cycle, which can be seen in the temporal variation of rotation period of any solar layer (Chandra, & Vats 2011;Li et al 2012;Mei, Deng, & Wang 2018;Xu, Gao & Shi 2020).…”

“…The continuous temporal variation in synodic rotation period obtains through Lomb-Scargle Periodogram (LSP) analysis for each frequency during study period confirms the presence of prominent random component in the solar rotation (Figure 2). When scattered sidereal rotation period are smoothed to suppress the random component by taking 3-yr running mean, it hints the presence of longer duration periodic cycle, perhaps ∼11-yr Schwabe cycle (Mei, Deng, & Wang 2018) and ∼22 yrs Hale cycle (Xu, Gao & Shi 2020) (Figure 3).…”

Notes on the correlation between sudden stratospheric warmings and solar activity

“…However, according to current knowledge, there is no statistically significant impact of anthropogenic changes on the frequency of SSWs (e.g. Butchart et al, 2000;SPARC CCMVal, 2010;Mitchell et al, 2012;Hansen et al, 2014, Ayarzagüena et al, 2018. Moreover, some of the recent works show the enhancement of the frequency of SSWs under forcing of GHGs and ODSs (e.g.…”

Notes on the correlation between SSWs and solar activity

“…The F10.7 radio flux differs by the nature from the Lyman-alpha flux and sunspot numbers (Bruevich et al, 2014;Mei et al, 2018). Thus, the information about correlation coefficients for the same database and method potentially can be useful to identify possible reasons of correlation.…”