Anomalies in the evolution of global and large-scale solar magnetic fields as the precursors of several upcoming low solar cycles

Astronomy Letters (Impact Factor: 1.43). 04/2009; 35(4):247-252. DOI: 10.1134/S1063773709040045


Anomalies in the solar magnetic fields of various scales are studied. The polar magnetic field strength is shown to have decreased
steadily during the last three solar cycles. This is because the increase in the dipole magnetic moment observed from 1915
to 1976 has changed into a decrease in the last three cycles. At the same time, the medium scale magnetic fields (like those
of isolated coronal holes) have been unusually strong in the last cycle. As a result, the tilt of the heliospheric current
sheet is still about 30°. The large effective contribution from the medium scale fields to the total energy of the large-scale
fields is also confirmed by our calculations of the effective multipolarity index. The aa-index at the cycle minima is correlated
with the height of the succeeding maxima. The set of data considered may be indicative of the possible approach of a sequence
of low solar cycles.

Full-text preview

Available from:
  • Source
    • "Indeed, it is interesting to note that the changes of the circulation in the late 1970s-early 1980s coincided with the change of the N–S asymmetry of solar activity, the Southern hemisphere got dominant (Nagovitsyn , 1998; Georgieva et al., 2007). The change in the evolution of global magnetic fields of the Sun in this period (the growth of the dipole magnetic moment observed since 1915 to 1976 gave place to its decrease) was reported by Obridko and Shelting (2009). The period of the change in the largescale circulation and the correlation reversals in the 1920s was also rather interesting. "
    [Show abstract] [Hide abstract] ABSTRACT: In this work we studied the spatial and temporal structure of long-term effects of solar activity (SA) and galactic cosmic ray (GCR) variations on the lower atmosphere circulation as well as possible reasons for the peculiarities of this structure. The study revealed a strong latitudinal and regional dependence of SA/GCR effects on pressure variations in the lower troposphere which seems to be determined by specific features of baric systems formed in different regions. The temporal structure of SA/GCR effects on the troposphere circulation at high and middle latitudes is characterized by a roughly 60-year periodicity which is apparently due to the epochs of the large-scale atmospheric circulation. It is suggested that a possible mechanism of long-term effects of solar activity and cosmic ray variations on the troposphere circulation involves changes in the evolution of the polar vortex in the stratosphere of high latitudes, as well as planetary frontal zones.
    Full-text · Article · Feb 2012 · Advances in Space Research
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: We have quantitatively investigated the correlation between the relative sunspot number and magnitude of Sun's polar magnetic field in solar cycles 21-23 from May 1976 to November 2009. Sunspot number is in anti-correlation with average magnitude of polar field (r = -0.62, P < 0.001). Maximal positive correlation between the parameters was calculated when average magnitude of polar magnetic field was time-shifted forward on about 5.2 years (r=0.84, P
    Full-text · Article · Dec 2010
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: The parameter of cosmic ray fluctuations, which indicates the degree of IMF inhomogeneity, was introduced in order to quantitatively describe the dynamics of the galactic cosmic ray (GCR) intensity fluctuations during the geoeffective phases of the 11-year cycle. The 5-min data of the high-latitude neutron monitor at Oulu station (Finland) during cycles 20–23 was used in the calculations. The nonrandom non-Gaussian character of the GCR fluctuation parameter is caused by the nonstationary semiannual variation reflecting the transient nonstationary oscillatory process of sign reversal of the general solar magnetic field. This transient oscillatory process is responsible for the maximal geoeffectiveness and duration of the phase of polarity reversal, which manifests itself in a sharp and deep GCR intensity minimum during the final stage of the field sign reversal. The invariant of the 11-year “amplitude-duration” cycle was confirmed on a new basis: the LF drift of the “low” cycle period was detected, which was observed in an increase in the duration of cycle 23 we anticipated.
    Preview · Article · Apr 2011 · Geomagnetism and Aeronomy
Show more