Prediction of the smoothed monthly mean sunspot numbers for solar cycle 24

The prediction for the smoothed monthly mean sunspot numbers (hereafter SMSNs) of solar cycle 23, which was given with a similar cycle method proposed by us at the beginning time of cycle 23, is analyzed and verified in this paper. Using our predicted maximum SMSN and the ascending length for solar cycle 24, and as- suming their relative errors to be respectively 20% and ± 7 months, solar cycles 2, 4, 8, 11, 17, 20 and 23 are selected to be the similar cycles to cycle 24. The selected solar cycles are divided into two groups. The first group consists of all the selected cycles; while the second group consists of only cycles 11, 17, 20 and 23. Two SMSN time profiles then may be obtained, respectively, for the two similar cycle groups. No significant difference is found between the two predicted time profiles. Consid- ering the latest observed sunspot number so far available for cycle 23 and the pre- dictions for the minimum SMSN of cycle 24, a date calibration is done for the ob- tained time profiles, and thus, SMSNs for 127 months of cycle 24, from October 2007 to April 2018, are predicted.

Influence of Solar Cycle Variations on Solar Spectral Radiation

The climatic changes associated with solar variability are largely caused by variations in total solar irradiance and solar spectral irradiance with solar activity. Thus the spectral composition of solar radiation is crucial in determining atomspheric structure. The variations in solar spectrum depend on the varied solar spots. Recently, evidence for a strong effect of solar activity on terrestrial isolation on ground-based measurements carried out by the National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Egypt (lat. 29?52'N and long. 31?20'E) during (1990-2000) were presented. Specifically, a strong increase of terrestrial isolation with sunspot number as well as a decline of the solar spectrum with solar activity was reported. Daily measurements of the solar radiation between 280 nm and 2800 nm were made by Eppley Pyranometer and Pyrheliometer instruments. The decreasing at the range 280 - 530 nm and 530 - 630 nm are represented less than 50% of direct solar radiation and the stability of at the range 630 - 695 nm and 695 - 2800 nm it mean that;some of difference radiation is appear in diffused radiation which allow to height of the temperature as much as the largest associated with significance as it appears from the curves of relative humidity.

Statistical study on great geomagnetic storms during solar cycle 23

Characteristics of great geomagnetic storms during solar cycle 23 were statistically investigated. Firstly, we focused on the uniqueness of solar cycle 23 by analyzing both the great storm number and sunspot number from 1957 to 2008. It was found that the relationship between the sunspot number and great storm number weakened as the activity of the storms strengthened. There was no obvious relationship between the annual sunspot number and great storm number with Dst≤-300 nT. Secondly, we studied the relationship between the peak Dst and peak Bz in detail. It was found that the condition Bz〈-10 nT is not necessary for storms with Dst≤-100 nT, but seems necessary for storms with Dst≤-150 nT. The duration for Bz≤-10 nT has no direct relationship with the giant storm. The correlation coefficient between the Dst peak and Bz peak for the 89 storms studied is 0.81. After removing the effect of solar wind dynamic pressure on the Dst peak, we obtained a better correlation coefficient of 0.86. We also found the difference between the Dst peak and the corrected Dst peak was proportional to the Dst peak.

太阳10.7cm射电辐射流量预报方法初探

引进“相似周”方法,通过两种方式对第23周太阳10.7cm辐射流量(E10.7)月均值进行预报和预报试验.由“相似周”方法得到的第23周太阳黑子数月均平滑预测值来预测F10.7月均值和直接采用“相似周”方法对F10.7月均平滑值进行预测.通过对两种预报试验结果分析,得到以下结论. (1)两种预测结果与实际都比较吻合,都得到双峰结构. (2)直接通过相似胤预测的F10.7的月均值结果较间接通过太阳黑子数的预测结果所推断的F10.7预测结果更接近实际观测结果. (3)使用“相似周”预报方法,可以给出F10.7比较精细的剖面结构,这是其他普通预报方法很难做到的.

利用EMD方法提取太阳活动周期成分

EMD(经验模态分解)方法在处理非线性及非平稳时间序列时表现出了很大的优势和应用潜力．利用EMD方法研究太阳活动周期,对110年(1894—2003)和55年(1949—2003)的太阳黑子数月均值进行分解,分别得到一系列模式和一个趋势项,其中都可能包含有1．3至1．4年周期分量,25至30个月QBO(准双年振荡)分量,11年太阳周分量和22年Hale周分量．其中11年周期分量幅度最大,变化特征与太阳黑子数原始数据具有很高的相似性．不同于传统方法,EMD方法给出了太阳活动在不同时间尺度上各自分离的变化特征．

用太阳活动拟合近2000年的温度变化

利用两个反映太阳活动的指标—太阳黑子相对数及太阳黑子周期长度—来拟合近 2 0 0 0年我国的温度变化 ,其结果与近 2 0 0 0年 ,特别是近 70 0年来温度变化的总趋势基本一致。同时拟合了 12 0年来北半球温度的演变 ,结果表明 :太阳活动是引起 10 1年以上气温变化的基本因素 ,近十多年来温室气体的作用似乎不可忽略。

利用相似周方法预测第24活动周开始时间

利用相似周方法对第24活动周的开始时间与第23活动周下降相后期的太阳黑子数进行了预报.根据第23周已经出现的特征参量和下降相的形态特征,选取9,10,11,15,17和20等六个太阳活动周作为第23周下降相的相似周,对第24周开始时间进行预报.预报结果显示,第24活动周的开始时间为2007年5±1月,黑子数平滑月均极小值为7.1±2.6,第23太阳活动周长度为11.1年.与其他研究者的预报结果相比较,本文给出的结果与文献[11[和[12]及MSFC的结果比较一致.通过对相似周方法在下降相预测太阳活动周结束时间的研究讨论,及对第23周上升阶段的太阳黑子数和F_(10.7)平滑月均值预报结果的评估,可以看出,相似周预报方法在太阳活动周长期预报中是很有应用价值的.

f_oF_2月中值太阳循环变化及单站谱模型研究

利用我国9个电离层观测站第21和22太阳周大约20年的foF2月中值数据,分析太阳活动和地磁活动对电离层foF2的影响,结果显示白天和夏季夜间foF2和太阳黑子数R之间存在着明显非线性关系,并且随着纬度的降低逐渐增强.当回归分析加入地磁Ap指数时,多重回归模型与实测值误差进一步减小,说明同时考虑太阳活动和地磁活动的非线性影响能够更好地描述foF2的变化.基于foF2与太阳黑子数R及地磁指数Ap之间的非线性统计关系,利用Fourier级数建立9个单站谱模型,并与国际参考电离层IRI进行了比较,精度有一定提高.

磁暴数统计特性研究

Dst是一个表征磁暴强度的空间天气指数.通过统计1957—2008年发生的中等磁暴(-100<Dst≤-50 nT)和强磁暴(Dst≤-100 nT)在太阳活动周上升年、极大年、下降年和极小年的时间分布情况,分析其随季节变化的统计特性,进而讨论了引起磁暴的原因.结果表明,对于同一太阳活动周,极大年地磁暴发生次数远大于极小年地磁暴的发生次数,这与太阳黑子数的变化趋势是一致的;通常太阳活动周强磁暴出现双峰结构,而第23周中等磁暴出现双峰结构,强磁暴则出现三峰结构,这可能与1999年强磁暴发生次数异常少,使1998年凸显出来的现象有关;磁暴主要发生在分季,随着Dst指数的增加,磁暴发生次数明显增加.

太阳黑子活动周期特征的神经网络和小波分析

太阳黑子数是描述太阳活动水平的主要指标,太阳活动直接影响日地环境。依据前人对太阳黑子数的观测资料,采用BP神经网络及小波分析和自相关相结合的方法,分析了1770-1869年的太阳黑子数年均值,得出了太阳黑子存在11-12年周期的结论,并对该算法及噪声鲁棒性进行了仿真。实验结果表明,该算法对研究太阳活动的本质规律是有效的。两种方法与其他方法,如自相关法、功率谱法等,进行了相比,不仅得出与实际一致的结论,而且对噪声有较强的鲁棒性,这对含噪信号的分析研究是很有意义的。

强磁暴的时间分布特性

对比分析1957-2008年间Dst≤一100 nT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≤一100nT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。

太阳黑子的世纪周期及对24、25活动周的预报

太阳活动除了具有公认的11a周期以外,还存在着一个80～120 a变化的世纪周期,也称为Gleissberg周期。使用傅里叶变换和小波分析的方法,分析了1700～2008年的年均黑子数世纪周期的变化规律。得到结果:在太阳活动世纪周期的低谷期,所对应11 a太阳周的极大年和极小年的黑子数目都比其他太阳周的低。在这300多年里,世纪周期的周期长度也有变化。由世纪周期的变化趋势,预测第24、25太阳活动周将处于世纪周期的低谷期。通过对以前3个世纪周期的谷期黑子数求平均的方法,得到第24、25太阳周极大年年均黑子数为63.6±21.1,极小年的为2.2±2.1。这些结果有助于理解当前太阳活动反常宁静这一现象。

中国部分地区电离层临界频率的研究

本文采用旬滑动平均法,从设在南中国海口、广州、重庆三垂测台站和北中国兰州、北京、长春、乌鲁木齐、满洲里五垂测台站所获得的8万个数据中,分析了1964～1976年期间 F_2层临频率正午值,子夜值的季节变化和逐年变化以及它们同太阳黑子数的关系。并将南北中国各台站临界频率变化进行了对比分析。

Periodicity of sunspot activity in the modern solar cycles

Sunspot number, sunspot area and sunspot unit area are usually used to show sunspot activity. In this paper, periodicity of sunspot activity of modern solar cycles has been investigated through analyzing the monthly mean val- ues of the three indices in the time interval of May 1874 to May 2004 by use of the wavelet transform. Their global power spectra and local power spectra are given while the statistical tests of these spectra are taken into account. The main results are (1) the local wavelet power spectrum of the sunspot number seems like that of the sunspot area, indicat- ing that the periodicity of the both indices is similar. The local power spectrum of the sunspot unit area resembles the local power spectra of the previous two indices, but looks more complicated. (2) the possible periods in sunspot activity are about 10.6 (or 10.9 years for the sunspot unit area), 31, and 42 years, and the period of about 10.6 years is statisti- cally significant in the considered time. For the periods of about 31 and 42 years, their power peaks are under the 95% confidence level line but over the mean red-noise spectral line, and for the other rest periods, their power peaks are even under the mean red-noise spectral line, which are sta- tistically insignificant. (3) the local power of the three periods is higher in the late stage than in the early stage of the con- sidered time. (4) the period characteristics of the three indi- ces, shown in the global power spectra and the local power spectra, are similar but there is difference in detail.

太阳黑子活动周期规律分析及趋势预测

针对太阳黑子活动趋势预测问题,以提高预报可信度、减少预测误差为目标,基于1700年以来太阳黑子相对数月、年资料,依据太阳黑子活动周期特征分析,得出太阳黑子具有100a大周期、11a小周期、100a大周期之间存在2~3个连续低值小周期的活动规律,进而对318a太阳黑子相对数系列进行阶段划分并进行周期性规律特征分析。采用拟合优度和纳什效应系数对2019—2030年太阳黑子相对数所在小周期轨迹段与历史小周期片段进行相关性分析、挑选最相似的历史小周期轨迹段的方法,以预报2019—2030年太阳黑子活动趋势。结果表明:2024年为下一小周期峰值年、2030年为下一小周期谷值年份。研究成果可以为以用太阳黑子相对数作为影响因子进行洪水灾害预报提供基础信息。

基于天文效应的流域性特丰水年预报方法及应用

针对造成水库特丰水年的天文条件问题,为了提高水库特丰水年预报结果的可信度,以国家电网公司调度区域内的15座大型水库特丰水年为研究对象,选用太阳黑子相对数、月球赤纬角2个天文因子,采用点聚图法,绘制水库年入库流量与太阳黑子关系分布图、水库年入库流量与月球赤纬角关系分布图、水库年入库流量天文效应区图,分析水库特丰水年在特定天文条件范围内的聚类关系,使15座水库特丰水年平均出现概率提高到正常出现概率的5.1倍。结果表明:水库的特丰水与太阳黑子、月球赤纬角密切相关,在特定的太阳黑子、月球赤纬角范围内高频率发生;基于流域同步性分析,从形成特丰水年的天文条件、天文周期、可公度结构等方面,预报2020年发生1964年型全国多流域水库特丰水、流域大洪水的概率大。

基于神经网络预测太阳黑子变化

太阳黑子变化是太阳强磁扰动的表征。结合长短期记忆单元神经网络和一维卷积神经网络预测太阳黑子变化,使用3种不同的数据集,分别为1700—2020年年均太阳黑子数(yearly mean sunspot number,YSSN)、1749—2021年月均太阳黑子数(monthly mean sunspot number,MSSN)和1874—2021年月均太阳黑子面积(monthly mean sunspot area,MSSA)。首先,基于YSSN数据集,预测得到2021年YSSN以及第25太阳周YSSN,2025年预测值达到最大,其值为163.4;其次,基于MSSN数据集,预测得到2021年6月MSSN以及第25太阳周MSSN,2024年10月预测值达到最大,其值为245.9;接着,基于MSSA数据集,预测得到2021年6月MSSA,其值为73.1;最后,基于MSSA数据集,将纬度划分为13个分区,发现可以重建太阳黑子蝴蝶图。以上均表明神经网络方法为探测太阳黑子变化提供了新的解决思路。

Has the maximum of Solar Cycle 23 appeared?

In this note, we define firstly a compositive parameter as an index describing the level of solar activity in a solar cycle. The parameter is derived from a combination of the smoothed monthly mean sunspot number with the fluctuation of the associated monthly mean sunspot numbers to the smoothed one. Then, a method is developed for estimating the time of the appearance of a solar maximum based on the conception of similar cycles. An application ofthe method to the 23rd solar cycle shows that the maximum of the cycle should have appeared in the period from April to August 2000, and the descending phase of Cycle 23 has come.

A method to predict amplitude and date of maximum sunspot number

A method to predict the amplitude and date of the maximum sunspot number is introduced. The regression analysis of the relationship between the variation rate of monthly sunspot numbers in the initial stage of solar cycles and both of the maximum and the time-length of ascending period of the cycle showed that they are closely correlative. In general, the maximum will be larger and the ascending period will be shorter when the rate is larger. The rate of sunspot numbers in the initial 2 years of the 23rd cycle is thus analyzed based on these grounds and the maximum of the cycle is predicted. For the smoothed monthly sunspot numbers, the maximum will be about 139.2 ±18.8 and the time-length of ascending period will be about 3.31 ±0.42 years, that is to say, the maximum will appear around the spring of the year 2000. For the mean monthly ones, the maximum will be near 170.1±22.9 and the time-length of ascending period will be about 3.42 ±0.46 years, that is to say, the appearing date of the maximum

黑河莺落峡站径流变化的影响因素分析

以黑河干流出山口径流控制站莺落峡水文站1960-2004年45年的径流序列为基础数据,采用相关分析、交叉谱分析、统计规律分析、降水—径流双累积曲线法等研究了全球变化、太阳黑子活动、ENSO循环和下垫面变化对黑河干流出山径流变化的影响。结果表明:①全球变化对莺落峡站径流变化影响较大;②莺落峡站年径流与太阳黑子相对数两序列在2年和3.3年两个振动周期上存在显著的相关关系,但在这两个存在显著相关关系的振动周期上太阳黑子相对数的周期波动变化都落后于莺落峡站年径流的周期波动变化;③ENSO循环对莺落峡站年径流变化有一定的影响,但是,ElNino事件和LaNina事件对莺落峡站年径流的影响时间持续较短,对事件发生当年的径流变化影响较大,对事件发生次年的径流变化影响较小;④流域下垫面变化对莺落峡站年径流量的变化影响较小。