Relation between the photospheric magnetic field and phases of a 22-year solar cycle

Strong magnetic fields at latitudes of ±40° are studied on the basis of synoptic maps of the photospheric magnetic field from the Kitt Peak Observatory (1976–2003). The time variations and imbalance between positive and negative magnetic fluxes are studied for the Southern and Northern hemispheres. A change in the imbalance between fluxes of leading/following sunspots with a 22-year magnetic cycle is shown. The imbalance sign coincides with the sign of the global magnetic field in the Northern/Southern solar hemispheres, respectively.     

太阳绕太阳系质心运动22年周期及其与太阳活动的联系

对于太阳活动22年周期的成因机制长期存在着争论.本文借助于行星会合指数以及开普勒第三定律,对太阳绕太阳系质心运动周期进行了分析计算.结果发现,太阳绕太阳系质心运动存在22.1826年显著周期,这与太阳磁场变化的22.20年周期相吻合.并从太阳系角动量守恒的角度解释了两者之间的成因联系:在太阳绕太阳系质心运动的准22年周期中,太阳系质心与太阳质心逐步接近而后逐步分离.当两个质心之间的距离接近零的时候,太阳轨道角动量与自转角动量叠加,会导致太阳自转角速度的加快;当两个质心之间的距离逐渐远离的时候,则导致太阳自转角速度的减慢.这可能是引发太阳活动和太阳磁场变化的原因.这一新认识为太阳活动准22年周期成因机制的解释提供了新的线索和依据.     

Solar magnetic cycle: Peculiarities of the photospheric field distribution

Synoptic maps for 1976–2003 obtained at the Kitt Peak National Solar Observatory are used to analyze the longitudinal distribution of the solar photospheric magnetic field. The superposition of synoptic maps gives different pictures for the rise-maximum phase and the decline-minimum phase. Two characteristic periods correspond to different situations in the 22-year solar magnetic cycle in the course of which both the global magnetic field and the magnetic field of the leading sunspot in a group change their sign.     

Relationship between phases of quasi-decadal oscillations of total ozone and the 11-year solar cycle

Temporal variability of the relationship between the phases of quasi-decadal oscillations (QDOs) of total ozone (TO), measured at the Arosa station, and the Ri international sunspot number have been analyzed for the period of 1932–2009. Before the 1970s, the maximum phase of ozone QDOs lagged behind solar activity variations by about 2.5–2.8 years and later outstripped by about 1.5 years. We assumed that the TO QDOs in midlatitudes of the Northern Hemisphere were close to being in resonance with solar activity oscillations in the period from the mid-1960s to the mid-1970s and assessed the characteristic delay period of TO QDOs. The global distribution of phases and amplitudes of TO QDOs have been studied for the period from 1979 to 2008 based on satellite data. The maximum phase of TO QDOs first onsets in northern middle and high latitudes and coincides with the end of the growth phase of the 11-year solar cycle. In the tropics, the maximum oscillation phase lags behind by 0.5–1 year. The maximum phase lag near 40–50° S is about two years. The latitudinal variations of the phase of TO QDOs have been approximated.     

Beginning of the new solar cycle (cycle 24) in the large-scale open solar magnetic field

It is proposed to determined minimums of the 11-year solar cycles based on a minimal flux of the large-scale open solar magnetic field. The minimal fluxes before the finished cycle 23 (Carrington rotation CR 1904) and the started cycle 24 (CR 2054, April 2007) were equal to 1.8 × 10²² and 1.2 × 10²² μs, respectively. The long-term tendency toward an approach to a deep minimum of solar activity is confirmed. On the assumption that magnetic flux variations from minimums to maximums are proportional to each other, the anticipated value of the maximal Wolf number during cycle 24 is estimated as W _max = 80.     

Correlation between tropical cyclones and magnetic storms during cycle 23 of solar activity

The correlation between cyclic (11-year) variations in geomagnetic activity and tropical cyclogenesis during the completed solar activity cycle (cycle 23, 1996–2006) is studied. The total number of the semidiurnal intervals, with the mean values of the planetary a _p index not less than 40, for each year and the annual number of cyclones, regardless of their intensity, are used as the characteristics. The correlation coefficients r are calculated for each of the following four cyclogenesis regions: the Atlantic, northeastern and central Pacific, northwestern Pacific, and water areas of oceans and seas in the Southern Hemisphere. The conclusion that the correlation exists between magnetic storms and tropical cyclones in the Atlantic, obtained earlier by Ivanov [2006] on the basis of the data for 1996–2005, is confirmed. It has been found that the linear correlation coefficient r changed in different regions from positive to negative values: 0.55, 0, ?0.50, and ?0.50, respectively.     

A 22-year cycle in the F layer ionization of the ionosphere

The double-sunspot-cycle variation in terrestrial magnetic activity has been well known for about 30 years. In 1990 we examined and compared the low-solar-activity (LSA) part of two consecutive cycles and predicted from this database and from published results the existence of a double-sunspot-cycle variation in total electron content (TEC) of the ionosphere too. This is restricted to noontime when the semi-annual component is well developed. Since 1995 we have had enough data for the statistical processing for high-solar-activity (HSA) conditions of two successive solar cycles. The results confirm the LSA findings. The annual variation of TEC shows a change from an autumn maximum in cycle 21 to a spring maximum during the next solar cycle. Similar to the aa indices for geomagnetic activity the TEC data show a phase change in the 1-year component of the Fourier transform of the annual variation. Additionally we found the same behaviour in the F-layer peak electron density (N_max) over four solar cycles. This indicates that there exists a double-sunspot-cycle variation in the F-layer ionization over Europe too. It is very likely coupled with the 22-year cycle in geomagnetic activity.     

The signal of the 11-year solar cycle in the global stratosphere

The search for a signal of the 11-year sunspot cycle in the heights and temperatures of the lower stratosphere was previously successfully conducted for the northern hemisphere with a data set from the Freie Universität Berlin, covering four solar cycles. This work has been extended to the whole globe by means of the NCEP/NCAR reanalyses for the period 1968–1996. The re-analyses show that the signal exists in the southern hemisphere too, and that it is of nearly the same size and shape as on the northern hemisphere. The NCEP/NCAR reanalyses yield higher correlations with the solar cycle than do the Berlin analyses for the same period, because the interannual variability is lower in the NCEP/NCAR data.The correlations between the solar cycle and the zonally averaged temperatures at the standard levels between 200 and 10 hPa are largest between the tropopause and the 25 km level, that is, in the ozone layer. This may be partly a direct effect in this layer, because of more absorber (ozone) and more ultraviolet radiation from the sun in the peaks of the 11-year solar cycle. However, it is more likely to be mainly an indirect dynamical consequence of UV absorption by ozone in the middle and upper stratosphere.The largest temperature correlations move with the sun from one summer hemisphere to the other, and the largest height correlations move poleward from winter to summer.     

Certain regularities of solar activity variations during the 11-year cycle

The relationships between a number of the main characteristic parameters of the cycle—amplitude, half-width, and growth phase duration—and the approximation parameters, which make it possible to estimate the average behavior of 11-year activity, have been derived based on the obtained analytical representations of the regularities in the solar activity variations during the cycle. Quasibiennial variations proceeding against a background of the cycle are distinctly associated with the solar magnetic field structure and the structure representation variations in the corona and in the flux of the solar neutrino radiation. This makes it possible to state that all these processes are parts of the common physical mechanism of solar variability.     

The 11-year solar cycle affects the intensity and annularity of the Arctic Oscillation

We investigate the dependence of the Arctic Oscillation (AO) in winter on the solar activity by stratifying the data into overlapping intervals defined by percentiles of the 10.7 cm radio flux. The AO exhibits a complex dependence of its polarity, being weakest under low, but not minimum, solar activity, while strongest in solar maxima. The AO is more/less variable (i.e., more/less active) under a high/low solar activity. Under a moderate solar activity, its Pacific centre weakens and eventually disappears. These effects seem to be real in spite of a potential for mixing the AO with the second principal component due to sampling errors caused by insufficient spacing between the first two eigenvalues. The weakening of the Pacific centre is not a result of coincidence with major volcanic eruptions or specific phases of the El Niño-Southern Oscillation.     

行星运动与太阳自转角速度22年周期变化

Tlatov(2007)研究认为,太阳活动和太阳磁场变化的22年周期,可能与太阳自转速度的变化有关.可是关于太阳自转速度为什么呈现出22年的变化周期,尚未见到有说服力的解释.本文通过对行星会合指数、行星系质心绕太阳系质心的运动、太阳绕太阳系质心运动以及太阳自转角动量变化的分析,发现行星系统的会合与相互背离,导致了太阳系质心与太阳质心的背离和靠近,从而引发太阳绕太阳系质心旋转角动量与太阳自转角动量的分离与叠加.由此认为,这两种角动量间的转换是太阳自转角速度呈现22年周期性变化的原因.太阳自转速度极小值对应于行星会合指数极大值;而太阳自转速度极大值对应行星会合指数极小值.其中平均11年左右为太阳自转加速期,另外11年则为太阳自转减速期.这一发现,可能为太阳活动与太阳磁场变化22年周期的成因机制的解释提供一个新的线索.     

The effect of the 11-year solar cycle on the temperature in the lower stratosphere

Two temperature datasets are analyzed for quantifying the 11-year solar cycle effect in the lower stratosphere. The analysis is based on a regression linear model that takes into account volcanic, Arctic Oscillation (AO), Quasi-Biennial Oscillation (QBO) and El Nino Southern Oscillation (ENSO) effects. Under solar maximum conditions, temperatures are generally warmer for low- and mid-latitudes than under solar minimum, with the effect being the strongest in northern summer. At high latitudes, the vortex is generally stronger under solar maximum conditions, with the exception of February and to a lesser extent March in the Northern Hemisphere; associated with this positive signal at high latitudes, there is a significant negative signal at the equator. Observations also suggest that contrary to the beginning of the winter, in February–March, the residual circulation in the Northern Hemisphere is enhanced. A better understanding of the mechanisms at work comes from further investigations using the ERA-40 reanalysis dataset. First, a consistent response in terms of temperature and wind is obtained. Moreover, considering Eliassen-Palm (EP) flux divergence and residual circulation stream functions, we found an increased circulation in the Northern Hemisphere in February during solar maxima, which results in more adiabatic warming at high latitudes and more adiabatic cooling at low latitudes, thus demonstrating the dynamical origin of the response of the low stratosphere to the solar cycle.     

强磁暴的时间分布特性

对比分析1957--2008年间Dst≤-100nT的强磁暴数与太阳黑子数的变化趋势,发现太阳黑子数和Dst≤-100nT的强磁暴数的变化趋势有很好的一致性。进一步统计强磁暴在太阳周不同阶段的分布后发现,同一太阳周内60％以上的强磁暴出现在下降年,但从太阳周各个阶段的平均磁暴年发生率来看,强磁暴平均年发生率最高的年份仍然是太阳活动极大年。     

22-year cycle in the frequency of aurora occurrence in XIX century: Latitudinal effects

The 22-year variation in the frequency of aurora occurrence is found through an analysis of data of the Russian network of meteorological stations from 1837–1909. This variation is obtained in a form of asymmetry between even and odd solar cycles. We found that the nature of the 22-year variation depends on the latitude of the observation station. The annual number N of midlatitude auroras (geomagnetic latitudes Φ < 56°) for about three years at the end of the descending part of solar cycles is larger for the even cycles than for the odd. For high-latitude auroras (Φ ≥ 56°), the pattern is opposite: at the descending part of the solar cycle, N is larger in the odd cycles than in the even. For the high-latitude sector, asymmetry of the polar sun cycles (the period between two magnetic field reversals) is clearly observed: an increased N is observed during the whole odd polar cycle (which starts approximately at the maximum of the odd Schwabe cycle) as compared to the even cycle. Extrapolation of the modern picture of alternation of the sign of the global solar magnetic field back in time leads to the conclusion that the most geoeffective polar cycles in cycles 8–14 were those in which the polar magnetic field in the northen hemisphere was negative.     

太平洋及大洋洲地区地磁台太阳黑子周变化揭示的新问题

从太平洋4台的分析显示，APIA，GUAM和PAMATAI台Z分量的太阳黑子周变化与HONOLULU台的相位相反。可是，CANBERRA台的变化又和HONOLULU台同相。这种表现复杂的地方性差异，更反映出太阳黑子周变化源于外场之说的有问题的。     

On the sunspot cycle and the yearly variation of solar magnetic variation at istanbul

Summary The sunspot cycle variation of the amplitude of the solar magnetic variation has been investigated for magnetically moderate, quiet and disturbed days at Istanbul for the period 1949–1968, and fairly good linear relationship has been found forZ andD components of the earth's magnetic field. In some cases, it is rather difficult to say that there is any linear relationship between sunspot number and the amplitude of theH component of the earth's magnetic field. Meanwhile,K indices has also been considered with sunspot number by means of multiple regression analysis to overcome some uncertainties in this investigation.     

Causes of the divergence of magnetic tube photospheric bases in AR 10930

It is traditionally considered that the bases of emerging magnetic tubes, which are observed as magnetic elements (tube ??sections??) moving away from one another at the photospheric level, diverge completely because tubes are loop-shaped below the photosphere. It is assumed that there may be more causes. The possible Ampere force contribution to the divergence of the photospheric bases of a coronal magnetic rope (the magnetic tube system) with a current has been considered based on the evolution of photospheric magnetic fields in active region 10930 during December 8?C13, 2006. It has been concluded that the contributions of the emergence and horizontal motion caused by the Ampere force to the divergence of magnetic tube photospheric bases with a current can be comparable in magnitude.     

Estimate of the effect of the 11-year solar activity cycle on the ozone content in the stratosphere

Using spectral, cross-spectral, and regression methods, we analyzed the effect of the 11-year cycle of solar activity on the ozone content in the stratosphere and lower mesosphere via satellite measurement data obtained with the help of SBUV/SBUV2 instruments in 1978–2003. We revealed a high coherence between the ozone content and solar activity level on the solar cycle scale. In much of this area, the ozone content varies approximately in phase with the solar cycle; however, in areas of significant gradients of ozone mixing ratio in the middle stratosphere, the phase shift between ozone and solar oscillations can be considerable, up to π/2. This can be caused by dynamical processes. The altitude maxima of ozone sensitivity to the 11-year solar cycle were found in the upper vicinity of the stratopause (50–55 km), in the middle stratosphere (35–40 km), and the lower stratosphere (below 25 km). Maximal changes in ozone content in the solar cycle (up to 10% and more) were found in winter and spring in polar regions.