第22周以来的太阳黑子活动区

本文对第22周以来产生M级以上(包括M级)的X射线耀斑的太阳黑子活动区进行了统计分析,得到如下结果:(1)黑子活动区在南北半球上分布是不均匀的。具体表现是:南半球出现的黑子活动区多于北半球出现的。南半球活动较强的黑子群主要集中在80°,160°,200°和340°经度附近;北半球活动较强的黑子群主要集中在240°-280°和340°-360°经度带。(2)黑子群的面积(S_p)越大越易产生X级的X射线耀斑。对黑子群面积S_p在大于1000,500-1000和小于500单位时,它们产生X级的X射线耀斑的比率分别约为41％,33％和9％。     

第22太阳周地磁活动峰值及时间的预报(英文)

本文分析了从第13—22太阳周太阳和地磁活动特征和不同特点。应用自激励门限自回归时间序列模式及最大熵谱自回归数学方法去模拟和预报地磁aa指数年均值的峰值及时间。峰值是26—29,峰值时间是1994年春天或1993年秋天。第22太阳周地磁活动是中等活动的周。     

21～24太阳活动周首个高纬黑子和首个X级耀斑的半球特点与太阳活动的南北不对称性的关系

利用GOES和SDO卫星监测的太阳软X射线耀斑的数据,发现在21~24太阳活动周期间,第1个X级耀斑与第1个高纬黑子都出现在同一半球。与高纬黑子表征的太阳活动南北半球的不对称性一样,一个太阳活动周第1个X级耀斑的出现,很可能预示着首先出现X级耀斑的半球,其太阳活动将比另一半球更剧烈。     

太阳周围的慢激波与Alfvén起伏通过它的变化

本文处理了阿尔文(Alfven)起伏通过磁流体慢激波的变化.在阿尔文起伏源于太阳和太阳周围(2—6R)可能存在驻慢激波的前提下,分析了阿尔文起伏通过太阳周围的慢激波的情形,结果表明:(1)中性片附近低纬区是阿尔文起伏可以无条件通过的(或小)畸变区;(2)远离中性片高纬区只是低阿尔文马赫数时(M 0.3)的小畸变区;(3)阿尔文起伏源于太阳、太阳周围可能存在慢激波与空间观测到阿尔文起伏这三者是相容的,从而为太阳周围可能存在慢激波这一假设提供了一种间接支持.     

第22太阳周首次大质子事件的预测

本文通过对过去质子事件的分析,发现首次大质子事件都发生在每个太阳活动周开始后1.9年,从而得到第22太阳周首次大质子事件可能发生时段的预测。     

第21太阳周较大黑子群、耀斑的时空分布

本文对21太阳周(77—80年)较大黑子群(S_p≥250)和较大耀斑(2级以上)在太阳上的位置的分布,活动水平的周期性进行分析,得到如下结论:(1)活动经度在上升年和峰年不一样,峰年活动经度带较宽。(2)活动经度带有向小经度方向漂移的倾向。(3)活动复合体对活动经度带的形成起重要作用。(4)在一个太阳周中较大黑子群的纬度分布有类似“蝶形图”的分布。(5)南北半球分布不均匀,这种不均匀性交替变化有约210天的周期。(6)太阳活动呈周期性,上升年周期约86天,峰年约126天。     

2003年全国中学生天文奥林匹克竞赛决赛高年组试卷

姓名____出生日期:____年____月____日所在学校、年级:__________每题10分 cos X=1-X2/2(X以弧度为单位)可能用到的常数或者数值: 1.水星到太阳的距离是0.387天文单位,2003年5光速c=3×108m/s 月7日发生了一次水星凌日,请问在此之后,水星第一万有引力常数G=6.67×10-11m3/kg/s2 次到达东大距和西大距各是大约多少天之后?地球半径6400km 2.月亮绕地球公转的轨道平面和黄道只有一个非     

学术活动

《第一届张衡学术讨论会》于1990年8月23—29日在陕西临潼陕西天文台举行。这是一次我国(非太阳)天体物理学的联合学术讨论会,内容有:(1)近年来天体物理学的进展与展望评述报告会;(2)全国第七次脉冲星与活动天体讨论会;(3)全国第三次双星讨论会;(4)全国星系和宇宙学学术讨论会;(5)全国第一次空间天文学术讨论会。 这次会议的会务工作由陕西天文台承办,学术组织工作由南京大学天文系负责。     

太阳与地磁活动的1.3–1.7 yr振荡关系分析

太阳和地磁活动中的1.3–1.7 yr周期研究对于理解日地空间耦合系统中可能发生的物理过程十分重要.黑子是太阳光球层上最突出的磁场结构, Ap指数则是表征全球地磁活动水平的重要指标.使用同步压缩小波变换得到太阳黑子数和地磁Ap指数的1.3–1.7yr周期,并用互相关方法分析研究它们之间的相位关系.结果如下:(1)太阳黑子数和地磁Ap指数的1.3–1.7 yr周期呈现间歇性的演化特征,且随着时间的变化而不断变化;(2)地磁Ap指数在奇数活动周比相邻的偶数活动周的周期分量更高,表现出上下波动的变化特性;(3)地磁Ap指数和太阳黑子数的相位关系不是一成不变的,在大多数情况下地磁Ap指数滞后太阳黑子数,仅在第18和第22活动周黑子数在相位上滞后.     

AR5395的演化及有关日地事件的时间序列

1989年3月出现的太阳活动区5395号(以下简称AR5395)是第22太阳周峰期的一个高活动区,在其通过日面时,观测到11个X级、48个M级的X射线爆发,引起了自1961年以来最强的地磁暴。本文首先叙述AR5395过日面时的黑子群面积、射电辐射流量密度(2800MHz)及1A—8A软X射线最低值的日变化以及发生耀斑的时     

Long-Term Solar Cycle Evolution: Review of Recent Developments

The sunspot number series forms the longest directly observed index of solar activity and allows one to trace its variations on the time scale of about 400 years since 1610. This time interval covers a wide range from seemingly vanishing sunspots during the Maunder minimum in 1645–1700 to the very high activity during the last 50 years. Although the sunspot number series has been studied for more than a century, new interesting features have been found even recently. This paper gives a review of the recent achievements and findings in long-term evolution of solar activity cycles such as determinism and chaos in sunspot cyclicity, cycles during the Maunder minimum, a general behaviour of sunspot activity during a great minimum, the phase catastrophe and the lost cycle in the beginning of the Dalton minimum in 1790s and persistent 22-year cyclicity in sunspot activity. These findings shed new light on the underlying physical processes responsible for sunspot activity and allow a better understanding of such empirical rules as the Gnevyshev–Ohl rule and the Waldmeier relations.     

Predicting Solar Cycle 24 Using a Geomagnetic Precursor Pair

We describe using Ap and F_10.7 as a geomagnetic-precursor pair to predict the amplitude of Solar Cycle 24. The precursor is created by using F_10.7 to remove the direct solar-activity component of Ap. Four peaks are seen in the precursor function during the decline of Solar Cycle 23. A recurrence index that is generated by a local correlation of Ap is then used to determine which peak is the correct precursor. The earliest peak is the most prominent but coincides with high levels of non-recurrent solar activity associated with the intense solar activity of October and November 2003. The second and third peaks coincide with some recurrent activity on the Sun and show that a weak cycle precursor closely following a period of strong solar activity may be difficult to resolve. A fourth peak, which appears in early 2008 and has recurrent activity similar to precursors of earlier solar cycles, appears to be the “true” precursor peak for Solar Cycle 24 and predicts the smallest amplitude for Solar Cycle 24. To determine the timing of peak activity it is noted that the average time between the precursor peak and the following maximum is ≈?6.4 years. Hence, Solar Cycle 24 would peak during 2014. Several effects contribute to the smaller prediction when compared with other geomagnetic-precursor predictions. During Solar Cycle 23 the correlation between sunspot number and F_10.7 shows that F_10.7 is higher than the equivalent sunspot number over most of the cycle, implying that the sunspot number underestimates the solar-activity component described by F_10.7. During 2003 the correlation between aa and Ap shows that aa is 10 % higher than the value predicted from Ap, leading to an overestimate of the aa precursor for that year. However, the most important difference is the lack of recurrent activity in the first three peaks and the presence of significant recurrent activity in the fourth. While the prediction is for an amplitude of Solar Cycle 24 of 65±20 in smoothed sunspot number, a below-average amplitude for Solar Cycle 24, with maximum at 2014.5±0.5, we conclude that Solar Cycle 24 will be no stronger than average and could be much weaker than average.     

Prediction of the Beginning of Solar Activity Cycle 24 by the Similar Cycle Method

In this paper, the method of similar cycles is applied to predict the start time of the 24th cycle of solar activity and the sunspot numbers in the later part of the descending phase of cycle 23. According to the characteristic parameters and the morphological characters of the descending phase of cycle 23 and of cycles 9, 10, 11, 15, 17 and 20 (cycles selected as the similar cycles for the descending phase of cycle 23), the start time of cycle 24 is predicted to be in 2007 yr 5 ± 1m, the smoothed monthly mean spot number, 7.1 ± 2.6 and the length of the 23rd cycle, 11.1 yr. These results agree rather well with those stated in Refs.[11] & [12] as well as those of MSFC. Our work shows that the method of similar cycles can well be applied to the long-term prediction of solar activity.     

Coronal Activity During the 22-Year Solar Magnetic Cycle

The existence of a 22-year heliomagnetic cycle was inferred long ago not only from direct measurements of the solar magnetic field but also from a cyclic variability of a number of the solar activity phenomena. In particular, it was stated (a rule derived after Gnevyshev and Ohl (1948) findings and referenced as the G–O rule in the following) that if sunspot number Rz cycles are organized in pairs of even–odd numbered cycles, then the height of the peak in the curve of the yearly-averaged sunspot numbers Rz-y is always lower for a given even cycle in comparison with the corresponding height of the following odd cycle. Exceptions to this rule are only cycles 4 and 8 which, at the same time, are the nearest even cycles to the limits of the so-called Dalton minimum of solar activity (i.e., the 1795–1823 time interval). In the present paper, we are looking for traces of the mentioned G–O rule in green corona brightness (measured in terms of the Fexiv 530.3 nm emission line intensity), using data covering almost five solar cycles (1943–1994). It was found that the G–O rule seems to work within the green-line corona brightness, namely, when coronal intensity measured in an extended solar middle-latitude zone is considered separately from the rest of the solar surface. On the other hand, the same G–O rule is valid at the photospheric level, as the heliographic latitudinal dependence of sunspot numbers (1947–1984) shows.     

High Flare Activity in the Late Declining Phase of Cycle 23

In the declining phase of the current solar cycle (23), a large number of major flares were produced. In this cycle, the monthly sunspot number continuously remained below 100 since October 2002. However, during four epochs since then, flare activity became very high. Compared to this, each of cycles 21 and 22 produced only one epoch of high activity in the declining phase. In the declining phase of cycle 20, similarly to this cycle, there were four epochs of high flare activity. During 2003 and 2004, the distribution of flare sizes measured in GOES classes was much harder (i.e., proportionately more energetic flares) than during the maximum years. Such pronounced hardening of the size distribution was not observed in the previous cycles. It is of theoretical interest to understand why some cycles are very active in the declining phase, and the high level of activity in the declining phase has practical implications for planning solar observations and forecasting space weather.     

Analysis of the 1.3–1.7 yr Oscillation Relationship between Solar and Geomagnetic Activities

The study on the 1.3–1.7 yr period of the solar and geomagnetic activities is very important for understanding the possible physical processes in the solar-terrestrial coupling system. The sunspot is the most prominent magnetic field structure in the solar photosphere, and the Ap index is an important indicator for the global geomagnetic activity level. The 1.3–1.7 yr period for the sunspot number and the geomagnetic Ap index is obtained by the synchro-squeezing wavelet transform, and the phase relationship between them is studied by the cross-correlation analysis. The main results are as follows: (1) The 1.3–1.7 yr period of the geomagnetic Ap index and sunspot number exhibits an intermittent evolutionary characteristics, and changes continuously with the time; (2) the geomagnetic Ap index has a higher periodic component in the odd solar cycles than the neighboring even solar cycles, which is characterized by fluctuations; (3) the phase relationship between the geomagnetic Ap index and the sunspot number is not always invariant, in most cases the geomagnetic Ap index lags behind the sunspot number, except in the 18th and 22th solar cycles.     

Prediction of Solar Cycle 24 Using Sunspot Number near the Cycle Minimum

Correlations between monthly smoothed sunspot numbers at the solar-cycle maximum [R _max] and duration of the ascending phase of the cycle [T _rise], on the one hand, and sunspot-number parameters (values, differences and sums) near the cycle minimum, on the other hand, are studied. It is found that sunspot numbers two?–?three years around minimum correlate with R _max or T _rise better than those exactly at the minimum. The strongest correlation (Pearson’s r=0.93 with P<0.001 and Spearman’s rank correlation coefficient r _S=0.95 with P=9×10^?12) proved to be between R _max and the sum of the increase of activity over 30 months after the cycle minimum and the drop of activity over 30 or 36 months before the minimum. Several predictions of maximal amplitude and duration of the ascending phase for Solar Cycle 24 are given using sunspot-number parameters as precursors. All of the predictions indicate that Solar Cycle 24 is expected to reach a maximal smoothed monthly sunspot number (SSN) of 70?–?100. The prediction based on the best correlation yields the maximal amplitude of 90±12. The maximum of Solar Cycle 24 is expected to be in December 2013?–?January 2014. The rising and declining phases of Solar Cycle 24 are estimated to be about 5.0 and 6.3 years, respectively. The minimum epoch between Solar Cycles 24 and 25 is predicted to be at 2020.3 with minimal SSN of 5.1?–?5.4. We predict also that Solar Cycle 25 will be slightly stronger than Solar Cycle 24; its maximal SSN will be of 105?–?110.     

Phase Relationship Between Sunspot Number, Flare Index and Solar Radio Flux

To understand better the variation of solar activity indicators originated at different layers of the solar atmosphere with respect to sunspot cycles, we carried out a study of phase relationship between sunspot number, flare index and solar radio flux at 2800 MHz from January 1966 to May 2008 by using cross-correlation analysis. The main results are as follows: (1) The flare index and sunspot number have synchronous phase for cycles 21 and 22 in the northern hemisphere and for cycle 20 in the southern hemisphere. (2) The flare index has a noticeable time lead with respect to sunspot number for cycles 20 and 23 in the northern hemisphere and for cycles 22 and 23 in the southern hemisphere. (3) For the entire Sun, the flare index has a noticeable time lead for cycles 20 and 23, a time lag for cycle 21, and no time lag or time lead for cycle 22 with respect to sunspot number. (4) The solar radio flux has a time lag for cycles 22 and 23 and no time lag or time lead for cycles 20 and 21 with respect to sunspot number. (5) For the four cycles, the sunspot number and flare index in the northern hemisphere are all leading to the ones in the southern hemisphere. These results may be instructive to the physical processes of flare energy storage and dissipation.     

太阳活动23周上升阶段质子事件的 预报分析

以２２周太阳活动低年（１９９３－１９９５）质子事件及其对应活动区的综合分析结果为判据,预报２３周太阳活动上升阶段的质子事件．从１９９７年１１月开始到１９９８年１２月,用该方法预报的质子事件共６个,报准３个,不确定一个,虚报１个,漏报１个（太阳背面产生的事件）．本文对用该方法预报的结果进行了分析讨论,并与世界警报中心的预报结果进行了比对,结果表明,该方法对于质子事件的短期预报是有效的．