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arXiv 2204.04818astro-ph.SR
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太阳活动周期的预测与反演

Forecast and backcast of the solar cycles

K M Hiremath

摘要:

太阳活动周期被建模为受迫和阻尼谐振子,并且通过将正弦和瞬态部分的方程非线性拟合到太阳黑子和辐照度(太阳黑子的代表)来估计这种谐振子的振幅、频率、相位和衰减因子1700-2008年的数据。我们发现:(i)正弦部分的振幅和频率(或周期为$\sim$ 11 yr)在所有的太阳活动周中保持恒定;(ii)瞬态部分的振幅与正弦部分的相位锁定;(iii)瞬态部分的周期和衰减因子(远小于1)在所有的太阳活动周中保持近似恒定。正弦部分的振幅和频率的恒定性以及来自瞬态部分的非常小的衰减因子表明,太阳活动周期主要由可能与长周期($\sim$ 22 yr)Alfven振荡兼容的持续振荡部分组成。对于所有的太阳活动周,我们利用估计的物理参数(振幅、相位和周期),通过自回归模型,对太阳活动周进行了预测(特别是对即将到来的第25太阳活动周)和反推(以检查是否存在蒙德极小型太阳活动)。我们发现即将到来的第25个太阳活动周的振幅与前一个太阳活动周的振幅几乎相同。我们还发现,太阳可能没有经历过一个深蒙德最低(MM)类型的活动在1645-1700 AD证实了一些古气候推断,MM类型的活动不会在不久的将来,直到至少200年。

英文摘要:

Solar cycle is modeled as a forced and damped harmonic oscillator and the amplitudes, frequencies, phases and decay factors of such a harmonic oscillator are estimated by non-linear fitting the equation of sinusoidal and transient parts to the sunspot and irradiance (proxy for the sunspot) data for the years 1700-2008. We find that:(i) amplitude and frequency (or period of $\sim$11 yr) of the sinusoidal part remain constant for all the solar cycles; (ii) the amplitude of the transient part is phase locked with the phase of the sinusoidal part; (iii) for all the cycles, the period and decay factor (that is much less than 1) of the transient part remain approximately constant. The constancy of the amplitudes and the frequencies of the sinusoidal part and a very small decay factor from the transient part suggests that the solar activity cycle mainly consists of a persistent oscillatory part that might be compatible with long-period ($\sim$22 yr) Alfven oscillations. For all the cycles, with the estimated physical parameters (amplitudes, phases and periods) and, by an autoregressive model, we forecast (especially for coming solar cycle 25) and backcast (to check whether Maunder minimum type solar activity exists or not) the solar cycles. We find that amplitude of coming solar cycle 25 is almost same as the amplitude of the previous solar cycle 24. We also find that sun might not have experienced a deep Maunder minimum (MM) type of activity during 1645-1700 AD corroborating some of the paleoclimatic inferences and, MM type of activity will not be imminent in near future, until at least 200 years.

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