异常的第24太阳活动周——新千年的第一个完整的太阳活动周

介绍自2007年下半年到现在的非常低的太阳活动状况:无黑子活动天数为16太阳活动周以来最多,不排除24周的无黑子天数是现代黑子周内最多的可能;高纬度(35°)黑子的纬度为12周最低;从2003年11月～2008年9月,较高纬度(20°)每月没有黑子或只有1个黑子,共计持续了58个月,也为12周以来第一次观测到;太阳风速度、太阳风压、10cm电磁波辐射、太阳极区磁场、太阳总光度辐射等参量都为有观测资料以来的最低.对于这种极低太阳活动的现象,介绍了从当前的日震观测给予的解释、也从Gleissberg周期的长尺度、超长太阳活动周期尺度给予了解释.依据目前的观测,我们确定24黑子活动周于2008年11月开始.综合多种经典太阳活动预报方法给出的对24周太阳活动水平的预报,以及美国国家航空航天局和美国国家海洋大气局对24周的未来发展趋势的预报,认为24周太阳活动水平估计比23周将要弱30%左右.异常的24太阳活动周为太阳物理和日地关系物理研究带来机遇.

The abnormal 24th solar cycle-The first complete solar cycle of the new millennium

The status of the extreme low solar activity since the second half of the year 2007 has been investigated.Cycle 24 has the most spotless days since cycle 16, and probably even since the modern cycles; latitudes of high-latitude （35°） sunspots belonging to a new cycle around the minimum time of the cycle are statistically the lowest at present, compared with those of other cycles; there are only one or no sunspots in a month appearing at high latitudes （20°） for 58 months （from November 2003 to September 2008）, which is the first time observed since cycle 12 onwards.The solar wind velocity and press, F10.7, the polar solar magnetic field, solar total irradiance and so on reach their minima during the 23–24 cycle minimum time.In order to explain the present extreme low activity, introduced here is one possible mechanism related to helio-seismology, and two are proposed through the long-term running of the time scales of the Gleissberg period and those of millenniums.According to the present observations of the Sun, we determine that cycle 24 should start in November 2008.Solar activity is predicted to be 30% lower in cycles 24 than 23, based on the typical predictions of solar activity, including those given by NASA and NOAA.The abnormal 24th solar cycle should be an opportune moment for studying solar physics and solar-terrestrial physics.