共查询到20条相似文献，搜索用时 468 毫秒
1.
胡景耀 《中国天文和天体物理学报》1991,(3)
本文首次提出了从观测得到的具有星周尘埃壳层的恒星的能谱分布求取星周尘埃云的消光,并由此可通过改正星周消光改正后的星际消光法求得恒星距离的方法。 相似文献
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从微波爆发谱光薄部分辐射估计日冕磁场强度的一种方法周爱华（中国科学院紫金山天文台南京２１０００８）关键词回旋同步加速辐射谱，磁场强度１引言目前对太阳活动区物理和耀斑物理过程的真正认识仍是十分困难的，原因之一在于迄今为止人们仍未找到一种完善的，能被大家... 相似文献
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对国家天文台2．6～3．8GHz频谱仪在第23太阳活动周上升段(1996～1998)记录到的Ⅲ型爆发，与日冕物质抛射(CME)作了统计分析。发现微波Ⅲ型爆发可能是CME的先兆现象，并讨论了它们的辐射机制。 相似文献
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在研究暗条、耀斑等日面活动体的光谱时，观测谱线上都叠加上一定强度的背景光影响。如何消去这种影响对分析结果影响较大。目前，经典的方法有两大类：第一类是减法消去法，这种方法广泛为国内学者采用；第二类方法是除法消去法，即国外学者提出的（微）方模型方法。本文通过误差传递方法，比较了上述二大类方法，结果发现，所有方法的误差传递形式都是一样的，但（微）方模型的背景光误差可能要小些，至少从理论上讲要处理得合理些 相似文献
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差分法周跳探测与修复方法改进 总被引：3，自引：0，他引：3
在目前常用的周跳探测与修复方法基础上，提出了首先将观测资料按照观测历元不连续分成若干小弧段，然后利用差分法进行周跳探测，根据差分后周跳放大的特性判断周跳和野值，并确定其位置利用宽带组合和电离层组合的方法解算周跳大小。通过实例验证了其有效性。 相似文献
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本文将本文作者发展的辐流体动力学方程精细化了，在新的理论公式中，描述物质与辐射场的热力学变量被彻底分开了，这不仅使得理论自身内部更为一致，也给变星脉动理论计算带来方便，本文亦证明了新老理论是相容的。 相似文献
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一种根据斯托克斯轮廓分析推导太阳矢量磁场和热力学参量的空间三维结构的新方法在本文中提出．在不考虑散射和原子偏振的假设下，该方法由三个具有不同功能的操作分别作用于太阳大气中一层或二层斯托克斯轮廓组成．这三个操作构成一个运行单元．将此单元运用到从表面到光球底层所划分的大气层格点，然后对扫描区所有的点应用同样的程序便可获得太阳上观察区的矢量磁场和热力学参量的空间三维结构．文中给出了相应的流程图和三个操作的详细描述，并用简化了的程序对理论轮廓进行了拟合．结果表明此方法能较满意地导出矢量磁场尤其是磁场强度的三维空间结构，而热力学参量结构的推导还需进一步改进． 相似文献
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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. 相似文献
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我们对第12周至第22周的太阳黑子月平均面积数进行统计分析,并与相应的太阳黑子月平均数相比较,结果表明太阳黑子月平均面积数活动周与太阳黑子月平均数活动周有一定的关系。在多数情况下,太阳黑子出现最大值的时间与太阳黑子面积数出现最大值的时间上不一致;太阳黑子平滑月平均数活动周上升期与太阳黑子平滑月平均面积数上升期在大多数情况下不相同;太阳黑子平滑月平均数活动周平均效果的瓦德迈尔效应(Waldmeiereffect)一般要比太阳黑子平滑平均面积数的活动周明显;文中还对太阳黑子平滑月平均面积数活动周的特征进行了分析。 相似文献
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Verification of a Similar Cycle Prediction for the Ascending and Peak Phases of Solar Cycle 23 总被引：3，自引：0，他引：3
Reviews of long-term predictions of solar cycles have shown that a precise prediction with a lead time of 2 years or more of a solar cycle remains an unsolved problem. We used a simple method, the method of similar cycles, to make long-term predictions of not only the maximum amplitude but also the smoothed monthly mean sunspot number for every month of Solar Cycle 23. We verify and compare our prediction with the latest available observational results. 相似文献
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To better understand long-term flare activity, we present a statistical study on soft X-ray flares from May 1976 to May 2008.
It is found that the smoothed monthly peak fluxes of C-class, M-class, and X-class flares have a very noticeable time lag
of 13, 8, and 8 months in cycle 21 respectively with respect to the smoothed monthly sunspot numbers. There is no time lag
between the sunspot numbers and M-class flares in cycle 22. However, there is a one-month time lag for C-class flares and
a one-month time lead for X-class flares with regard to sunspot numbers in cycle 22. For cycle 23, the smoothed monthly peak
fluxes of C-class, M-class, and X-class flares have a very noticeable time lag of one month, 5 months, and 21 months respectively
with respect to sunspot numbers. If we take the three types of flares together, the smoothed monthly peak fluxes of soft X-ray
flares have a time lag of 9 months in cycle 21, no time lag in cycle 22 and a characteristic time lag of 5 months in cycle
23 with respect to the smoothed monthly sunspot numbers. Furthermore, the correlation coefficients of the smoothed monthly
peak fluxes of M-class and X-class flares and the smoothed monthly sunspot numbers are higher in cycle 22 than those in cycles
21 and 23. The correlation coefficients between the three kinds of soft X-ray flares in cycle 22 are higher than those in
cycles 21 and 23. These findings may be instructive in predicting C-class, M-class, and X-class flares regarding sunspot numbers
in the next cycle and the physical processes of energy storage and dissipation in the corona. 相似文献
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We find that the solar cycles 9, 11, and 20 are similar to cycle 23 in their respective descending phases. Using this similarity and the observed data of smoothed monthly mean sunspot numbers (SMSNs) available for the descending phase of cycle 23, we make a date calibration for the average time sequence made of the three descending phases of the three cycles, and predict the start of March or April 2008 for cycle 24. For the three cycles, we also find a linear correlation of the length of the descending phase of a cycle with the difference between the maximum epoch of this cycle and that of its next cycle.Using this relationship along with the known relationship between the rise-time and the maximum amplitude of a slowly rising solar cycle, we predict the maximum SMSN of cycle 24 of 100.2±7.5 to appear during the period from May to October 2012. 相似文献
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Longterm Prediction of Solar Activity Using the Combined Method 总被引：2，自引：0，他引：2
The Combined Method is a non-parametric regression technique for long-term prediction of smoothed monthly sunspot numbers. Starting from a solar minimum, a prediction of the succeeding maximum is obtained by using a dynamo-based relation between the geomagnetic aa index and succeeding solar maxima. Then a series of predictions is calculated by computing the weighted average of past cycles of similar level. This technique leads to a good prediction performance, particularly in the ascending phase of the solar cycle where purely statistical methods tend to be inaccurate. For cycle 23 the combined method predicts a maximum of 160 (in terms of smoothed sunspot number) early in the year 2000. 相似文献
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Instantaneous predictions of the maximum monthly smoothed sunspot number in solar cycle 23 have been made with a linear regressive model, which gives the predicted maximum value as a function of the smoothed sunspot numbers corresponding to a given month from the minimum in all preceding cycles. These predictions indicate that the intensity of solar activity in the current cycle will be at an average level. 相似文献
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The running correlation coefficient between the solar cycle amplitudes and the max-max cycle lengths at a given cycle lag is found to vary roughly in a cyclical wave with the cycle number, based on the smoothed monthly mean Group sunspot numbers available since 1610. A running average method is proposed to predict the size and length of a solar cycle by the use of the varying trend of the coefficients. It is found that, when a condition (that the correlation becomes stronger) is satisfied, the mean prediction error (16.1) is much smaller than when the condition is not satisfied (38.7). This result can be explained by the fact that the prediction must fall on the regression line and increase the strength of the correlation. The method itself can also indicate whether the prediction is reasonable or not. To obtain a reasonable prediction, it is more important to search.for a running correlation coefficient whose varying trend satisfies the proposed condition, and the result does not depend so much on the size of the correlation coefficient. As an application, the peak sunspot number of cycle 24 is estimated as 140.4±15.7, and the peak as May 2012± 11 months. 相似文献
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张勤 《紫金山天文台台刊》1999,18(2):147-150
本文给出了太阳２３ 周开始时间的确定、从开始到现在近两年间太阳活动的状况以及２３周上升期间的一些特点。分析表明,１９９６ 年１０ 月是２３ 周的第一个月,它的月平滑值是８ ．８ ;２３ 周的太阳活动虽然可能是高活动周,例如,国际推荐值为２０００ 年３ 月的１６０ ,但它可能不会超过前两周。根据上升期太阳活动的一些特征,还给出了在２３ 周峰年联测和空间灾害性扰动事件预报和预报方法研究中应注意的几个问题 相似文献
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The Empirical Mode Decomposition (EMD) and Auto-Regressive model (AR) are applied to a long-term prediction of sunspot numbers. With the sample data of sunspot numbers from 1848 to 1992, the method is evaluated by examining the measured data of the solar cycle 23 with the prediction: different time scale components are obtained by the EMD method and multi-step predicted values are combined to reconstruct the sunspot number time series. The result is remarkably good in comparison to the predictions made by the solar dynamo and precursor approaches for cycle 23. Sunspot numbers of the coming solar cycle 24 are obtained with the data from 1848 to 2007, the maximum amplitude of the next solar cycle is predicted to be about 112 in 2011-2012. 相似文献