Variations in the cyclic characteristics of solar magnetic activity on long time scales

Prolonged variations in the duration of the Schwabe-Wolf (～11 years) and Suess (～200 years) cycles have been analyzed using different experimental data. It was shown that the duration of the Schwabe-Wolf cycle on a 2000-year time scale varied monotonically (on average, increasing) and cyclically (with a period of several hundred years); periods of 10.4, 11.0, and 11.4 years predominate on the occurrence frequency histogram. The Suess cycle duration was 200–290 years during the Holocene and tended to increase in the past. This was accompanied by cyclic variations with a period of 2300–2500 years corresponding to the Hallstatt cycle. Arguments for the assumption that the Suess cycle duration decreased by a factor of more than 1.5 over the past half billion years are presented. This may indicate that the solar rotation characteristics and convection zone parameters varied on long time scales during the Sun’s evolution on the main sequence.     

Regional instrumental series in reconstructions of global changes in the Earth’s climate

The possibility to apply long-term regional series to reconstruct the Earth’s global temperature in the past is considered. It is shown using symbolic analysis methods that significant (on the so-called order patterns) are relations of time series of St. Petersburg temperature with certain regional and global series. New sets of global temperature reconstructions, starting from the mid-18th century, are constructed on the basis of the previously proposed MSR and DPS methods.     

Observation and analysis of solitary internal waves in the coastal zone of the Sea of Okhotsk

Experimental data on the measurement of solitary internal waves in the coastal zone of the Sea of Okhotsk are reported. The non-linear and dispersion coefficients of the Korteweg-de Vries (KdV) equation are determined for weakly non-linear disturbances of the first mode. The shapes and parameters of solitary waves are compared with the corresponding parameters of solitons. It is shown that at least ten observed solitary waves are similar to the KdV solitons. Histograms of the distribution of the amplitudes, duration, and spatial dimensions are plotted for a large number of solitary waves.Translated by Mikhail M. Trufanov.     

Series of classical solar activity indices: Kislovodsk data

We present data on the series of solar activity indices, Wolf sunspot numbers W and total sunspot areas S, obtained at the Kislovodsk high-altitude station of the Pulkovo Observatory. The problem of properly extending the 133-year-long Zürich series of W and the 102-year-long Greenwich series of S, which were discontinued in 1980 and 1976, respectively, is emphasized. We stress that the Kislovodsk data have retained mutual homogeneity with the classical series until now and that they are preferred for extension. The question under consideration is of fundamental importance in studying the solar activity variations on long time scales and related processes in the Sun-Earth system.     

The Maunder minimum: North-south asymmetry in sunspot formation,mean sunspot latitudes,and the butterfly diagram

An approach to reconstructing solar activity in the past is used to study its time evolution. It is already possible to reconstruct not only the general level of solar activity on long timescales, but also particular aspects of its development: sunspot dominance in either hemisphere, the drift and latitude spread of the sunspot-formation zone, and features in the spatial distribution of the activity at specific epochs, such as the Maunder minimum.     

Variations of microwave emission from solar active regions

Based on observational data obtained with the RT-22 Crimean Astrophysical Observatory radio telescope at frequencies of 8.6 and 15.4 GHz, we investigate the quasi-periodic variations of microwave emission from solar active regions with periods T_p<10 min. As follows from our wavelet analysis, the oscillations with periods of 3–5 min and 10–40 s have the largest amplitudes in the dynamic power spectra, while there are virtually no oscillations with T_p<10 s. Our analysis shows that acoustic modes with T_p?1 min strongly dissipate in the lower solar corona due to thermal conduction losses. The oscillations with T_p=10–40 s are associated with Alfvén disturbances. We analyze the influence of acoustic and Alfvén oscillations on the thermal mechanisms of microwave emission in terms of the homogeneous model. We discuss the probable coronal heating sources.     

Analysis of Oscillatory Modes of the Magnetic Field of Solar Facular Formations

Geomagnetism and Aeronomy - Quasi-periodical variations in the magnetic fields of long-living, small-scale magnetic structures, solar facular formations (FFs), are analyzed. We used the method of...     

Some Features of the Two Sunspot Group Populations’ Properties

Geomagnetism and Aeronomy - This paper describes some features of the two sunspot group populations’ properties: Large Long-living Groups, LLG, and Small Short-living, SSG (each distributed...     

Periods of Extremely High Rates of the Production of Cosmogenic 14C and Temperature Variation According to Data on the 40Ar Content in the Ice Layers for the Last 4000 Years

Geomagnetism and Aeronomy - The possible application of temperature reconstructions based on measurement of the 40Ar concentration in ice layers of the Greenland ice sheet to study past solar...