共查询到20条相似文献，搜索用时 109 毫秒
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本文分析了第２１ 、２２ 、２３ 太阳活动周的上升期２３ 个月（ 月均值） 太阳黑子资料。结果表明：太阳黑子相对数和面积南北不对称。２３ 周的太阳黑子相对数和面积（２３ 个月的平均） 高于２２ 周,但低于２１ 周。我们估计第２３ 周峰年为２０００ 年３ 月或１９９９ 年１２ 月。 相似文献
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文中评价了２３ 周以来北京天文台的短期太阳活动预报工作,Ｘ 射线耀斑的报准率为８９ ．６ ％ ,太阳质子事件的报准率为６２ ．５ ％ 。另外,还叙述了第２３ 周峰年北京天文台太阳活动预报工作的选题（ 包括研究课题和实施课题 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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日面高纬黑子与太阳活动 总被引：2，自引：0，他引：2
利用云南天文台太阳黑子观测资料,对太阳活动第１９ 周至第２２ 周日面高纬度（ 高于４０°） 的黑子群进行了统计．结果表明：高纬黑子面积绝大部分小于１００ ,平均５６ ,寿命大部分为１ ～３ 天,平均４ 天;黑子分类绝大部分为ＡＸＸ、ＨＳＸ、ＢＸＯ,其中ＡＸＸ 约占总数的一半．高纬黑子在日面南北半球上的不对称分布可用来预报该太阳周内的太阳活动在南北半球上的主次．由此预报２３ 周太阳活动将在南半球更活跃 相似文献
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张桂清 《中国天文和天体物理学报》1999,(2)
利用最新的太阳黑子观测资料和线性相关统计模式,对第２３太阳活动周的极大月平滑黑子相对数和黑子数的极大年均值进行预测．预报因子分别是每个太阳周上升相第２６个月的月平滑黑子相对数和第三年的黑子数年均值．预测结果表明,第２３周太阳黑子数的极大值不会高,极大月平滑黑子相对数为１１５．４±１４．９,极大年均值为１１８．９±１１．６．平滑黑子数极大不会出现在１９９９年,很可能出现在２０００年． 相似文献
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第23太阳活动周不会是强活动周 总被引：5，自引：1，他引：4
利用最新的太阳黑子观测资料和线性相关统计模式,对第２３太阳活动周的极大月平滑黑子相对数和黑子数物极大年均值进行预测,预报因子分别是每个太阳周上升相第２６个月的月平滑黑子相对数和第三年的黑子数年均值,预测结果表明,第２３周太阳黑子数的极大值不会高,极大月平滑黑子相对为１１５．４±１４．９,极大年均值为１１８．９±１１．６,平滑黑子数极大不会出现在１９９９年,很可能出现在２０００年。 相似文献
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本文简要的回顾了２２ 周太阳活动峰年,太阳射电观测研究概况,并根据一些新型的太阳射电设备的建立,对２３ 周峰年观测研究的选题,提出某些初步设想 相似文献
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Flare Index During the Rising Phase of Solar Cycle 23 总被引：1，自引：0，他引：1
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We analyze the evolution of cosmic ray intensity detected by six neutron monitors located at high altitude from 1990 to 1999,
that includes most of solar cycle 22 and the start of cycle 23. This set of neutron monitors covers a wide range of geomagnetic
cutoff rigidities. We discuss the most significant characteristics of the cosmic ray modulation during the period as: the
extraordinary decreases produced by the events of the first half of 1991, the significant two step evolution of the recovery
phase of solar cycle 22 and the start of cycle 23. We also determine the rigidity dependence of the different phases of the
modulation cycle. Cosmic ray intensity correlations with several solar activity parameters as sunspots, microwave flux at
10.7 cm and solar flares and with the intensity of the interplanetary magnetic field are studied. 相似文献
14.
Miyoshi Suzuki 《Solar physics》2012,278(2):257-267
We studied the solar rotation rate and its temporal change, using the sunspot data obtained during activity cycle 23 (1996 – 2006).
The equatorial rotation rate is nearly the same as in the former cycle 22, while the latitudinal gradient of differential
rotation considerably increased. Comparison of our results with others indicates the existence of a long-term periodicity
of about eight cycles in differential rotation. In addition, no significant asymmetry in differential rotation between the
northern and southern hemispheres during cycle 23 was found. The equatorial rotation rate and the latitudinal gradient of
the differential rotation in the period of cycle 23 are approximately constant, except for the initial and final phases in
the cycle. 相似文献
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We study solar modulation of galactic cosmic rays (GCRs) during the deep solar minimum, including the declining phase, of solar cycle 23 and compare the results of this unusual period with the results obtained during similar phases of the previous solar cycles 20, 21, and 22. These periods consist of two epochs each of negative and positive polarities of the heliospheric magnetic field from the north polar region of the Sun. In addition to cosmic-ray data, we utilize simultaneous solar and interplanetary plasma/field data including the tilt angle of the heliospheric current sheet. We study the relation between simultaneous variations in cosmic ray intensity and solar/interplanetary parameters during the declining and the minimum phases of cycle 23. We compare these relations with those obtained for the same phases in the three previous solar cycles. We observe certain peculiar features in cosmic ray modulation during the minimum of solar cycle 23 including the record high GCR intensity. We find, during this unusual minimum, that the correlation of GCR intensity is poor with sunspot number (correlation coefficient R=?0.41), better with interplanetary magnetic field (R=?0.66), still better with solar wind velocity (R=?0.80) and much better with the tilt angle of the heliospheric current sheet (R=?0.92). In our view, it is not the diffusion or the drift alone, but the solar wind convection that is the most likely additional effect responsible for the record high GCR intensity observed during the deep minimum of solar cycle 23. 相似文献
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In this work the galactic cosmic ray modulation in relation to solar activity indices and heliospheric parameters during the years 1996??C?2010 covering solar cycle 23 and the solar minimum between cycles 23 and 24 is studied. A new perspective of this contribution is that cosmic ray data with a rigidity of 10 GV at the top of the atmosphere obtained from many ground-based neutron monitors were used. The proposed empirical relation gave much better results than those in previous works concerning the hysteresis effect. The proposed models obtained from a combination of solar activity indices and heliospheric parameters give a standard deviation <?10?% for all the cases. The correlation coefficient between the cosmic ray variations of 10?GV and the sunspot number reached a value of r=?0.89 with a time lag of 13.6±0.4 months. The best reproduction of the cosmic ray intensity is obtained by taking into account solar and interplanetary indices such as sunspot number, interplanetary magnetic field, CME index, and heliospheric current sheet tilt. The standard deviation between the observed and calculated values is about 7.15?% for all of solar cycle 23; it also works very well during the different phases of the cycle. Moreover, the use of the cosmic ray intensity of 10?GV during the long minimum period between cycles 23 and 24 is of special interest and is discussed in terms of cosmic ray intensity modulation. 相似文献
17.
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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Using the smoothed time series of maximum CME speed index for solar cycle 23, it is found that this index, analyzed jointly with six other solar activity indicators, shows a hysteresis phenomenon. The total solar irradiance, coronal index, solar radio flux (10.7?cm), Mg?ii core-to-wing ratio, sunspot area, and H?? flare index follow different paths for the ascending and the descending phases of solar cycle?23, while a saturation effect exists at the maximum phase of the cycle. However, the separations between the paths are not the same for the different solar activity indicators used: the H?? flare index and total solar irradiance depict broad loops, while the Mg?ii core-to-wing ratio and sunspot area depict narrow hysteresis loops. The lag times of these indices with respect to the maximum CME speed index are discussed, confirming that the hysteresis represents a clue in the search for physical processes responsible for changing solar emission. 相似文献
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Although solar ultraviolet (UV) irradiance measurements have been made regularly from satellite instruments for almost 20 years, only one complete solar cycle minimum has been observed during this period. Solar activity is currently moving through the minimum phase between cycles 22 and 23, so it is of interest to compare recent data taken from the NOAA-9 SBUV/2 instrument with data taken by the same instrument during the previous solar minimum in 1985–1986. NOAA-9 SBUV/2 is the first instrument to make continuous solar UV measurements for a complete solar cycle. Direct irradiance measurements (e.g., 205 nm) from NOAA-9 are currently useful for examining short-term variations, but have not been corrected for long-term instrument sensitivity changes. We use the Mgii proxy index to illustrate variability on solar cycle time scales, and to provide complementary information on short-term variability. Comparisons with contemporaneous data from Nimbus-7 SBUV (1985–1986) and UARS SUSIM (1994–1995) are used to validate the results obtained from the NOAA-9 data. Current short-term UV activity differs from the cycle 21–22 minimum. Continuous 13-day periodicity was observed from September 1994 to March 1995, a condition which has only been seen previously for shorter intervals during rising or maximum activity levels. The 205 nm irradiance and Mgii index are expected to track very closely on short time scales, but show differences in behavior during the minimum between cycles 22 and 23. 相似文献
20.
Magnetic fields give rise to distinctive features in different solar atmospheric regimes. To study this, time variations of
the flare index, sunspot number and sunspot area, each index arising from different physical conditions, were compared with
the solar composite irradiance throughout cycle 23. Rieger-type periodicities in these time series were calculated using Fourier
and wavelet transforms (WTs). The peaks of the wavelet power of these periodicities appeared between the years 1999 and 2002.
We found that the solar irradiance oscillations are less significant than those in the other indices during this cycle. The
irradiance shows non-periodic fluctuations during this time interval. The peaks of the flare index, sunspot number and sunspot
total area were seen around 2000.4, 1999.9 and 2001.0, respectively. These periodicities appeared intermittently and were
not simultaneous in different solar activity indices during the three years of the maximum phase of solar cycle 23. 相似文献