Hale cycle in solar hemispheric radio flux and sunspots: Evidence for a northward shifted relic field

Solar and heliospheric parameters can depict notable differences between the northern and southern hemisphere. Although hemispheric asymmetries of some heliospheric parameters vary systematically with Hale cycle, this is not common for solar parameters. Also, no physical mechanism exists which can explain systematic hemispheric asymmetries. We use a novel method of high heliolatitudes to increase the fraction of one hemisphere in solar 10.7cm radio fluxes and sunspot numbers. We calculate sets of hemispheric high-latitude radio fluxes and sunspot numbers with increasing heliographic latitude during the last 75 years. We also normalise these fluxes by yearly means in order to study their continuous variation. We find that cycle maximum radio fluxes and sunspot numbers in each odd cycle (19, 21, 23) are larger at northern high latitudes, while in all even cycles (18, 20, 22 24) they are larger at southern latitudes. This alternation indicates a new form of Hale cycle variation in solar activity. Hemispheric differences at cycle maxima are 15% for radio flux and 23% for sunspot numbers. The difference is largest during cycle 19 and smallest in cycle 24. Continuous fluxes depict a Hale cycle in both hemispheres, with an opposite phase and amplitude of 5% in north and 4% in south. Hemispheric Hale cycle can be explained if there is a northward directed relic magnetic field, which is shifted northward. In odd cycles, the northern hemisphere is enhanced more than the southern hemisphere and, in even cycles, the northern hemisphere is reduced more than the southern hemisphere. The decrease of asymmetry during the 7 cycles can be explained if the relic shift oscillates at the 210-year Suess/deVries period. Gleissberg cycle consists of one off-equator excursion of the relic. Relic field in the Sun also offers a possibility for century-scale forecasting of solar activity.Comment: Accepted to be published in Astronomy and Astrophysic

A solar cycle lost in 1793--1800: Early sunspot observations resolve the old mystery

Because of the lack of reliable sunspot observation, the quality of sunspot number series is poor in the late 18th century, leading to the abnormally long solar cycle (1784--1799) before the Dalton minimum. Using the newly recovered solar drawings by the 18--19th century observers Staudacher and Hamilton, we construct the solar butterfly diagram, i.e. the latitudinal distribution of sunspots in the 1790's. The sudden, systematic occurrence of sunspots at high solar latitudes in 1793--1796 unambiguously shows that a new cycle started in 1793, which was lost in traditional Wolf's sunspot series. This finally confirms the existence of the lost cycle that has been proposed earlier, thus resolving an old mystery. This letter brings the attention of the scientific community to the need of revising the sunspot series in the 18th century. The presence of a new short, asymmetric cycle implies changes and constraints to sunspot cycle statistics, solar activity predictions, solar dynamo theories as well as for solar-terrestrial relations.Comment: Published by Astrophys. J. Let

Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?

Recent studies have led to speculation that solar-terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross-correlations between sunspot number, geomagnetic activity, and global surface temperature for the years 1868–2008, solar cycles 11–23. The data contain substantial autocorrelation and nonstationarity, properties that are incompatible with standard measures of cross-correlational significance, but which can be largely removed by averaging over solar cycles and first-difference detrending. Treated data show an expected statistically-significant correlation between sunspot number and geomagnetic activity, Pearson p < 10^(−4), but correlations between global temperature and sunspot number (geomagnetic activity) are not significant, p = 0.9954, (p = 0.8171). In other words, straightforward analysis does not support widely-cited suggestions that these data record a prominent role for solar-terrestrial interaction in global climate change. With respect to the sunspot-number, geomagnetic-activity, and global-temperature data, three alternative hypotheses remain difficult to reject: (1) the role of solar-terrestrial interaction in recent climate change is contained wholly in long-term trends and not in any shorter-term secular variation, or, (2) an anthropogenic signal is hiding correlation between solar-terrestrial variables and global temperature, or, (3) the null hypothesis, recent climate change has not been influenced by solar-terrestrial interaction