The Shape of Solar Cycle Described by a Modified Gaussian Function |
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Authors: | Zhanle Du |
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Institution: | 1.Central Astronomical Observatory at Pulkovo,Saint-Petersburg,Russia |
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Abstract: | The shape of each sunspot cycle is found to be well described by a modified Gaussian function with four parameters: peak size
A, peak timing t
m, width B, and asymmetry α. The four-parameter function can be further reduced to a two-parameter function by assuming that B and α are quadratic functions of t
m, computed from the starting time (T
0). It is found that the shape can be better fitted by the four-parameter function, while the remaining behavior of the cycle
can be better predicted by the two-parameter function when using the data from a few (about two) months after the starting
time defined by the smoothed monthly mean sunspot numbers. As a new solar cycle is ongoing, its remaining behavior can be
constructed by the above four- or two-parameter function. A running test shows that the maximum amplitude of the cycle can
be predicted to within 15% at about 25 months into the cycle based on the two-parameter function. A preliminary modeling to
the first 24 months of data available for the current cycle indicates that the peak of cycle 24 may probably occur around
June 2013±7 months with a size of 72±11. The above results are compared to those by quasi-Planck functions. |
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Keywords: | |
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