Standard prediction of solar cycles

Abstract

To make a long-term prediction of the solar cycle in a standard way (GOST 25645.302-83), it is necessary to know the instant of the activity minimum onset, the determination of which is difficult during the decline stage of the previous cycle. The dependence of the long-term prediction error on the time of shift (t) relative to the solar activity minimum instant (i.e., the situation when a certain time before the minimum onset, rather than the time of this minimum, is the initial point of calculations) has been studied. It has been indicated that one should not know the exact time of the activity minimum onset in order to make prediction according to GOST, and such a prediction can be performed with an approximately identical error if the lead time is t ∼ 1 year and more relative to the activity minimum onset. An analysis of the dependence of prognostic W _max values on t for cycles 18–23 indicated that prognostic W _max values are overestimated at small (to ∼ 1 year) uncertainties in the time of activity minimum onset. It has been obtained that W _max = 96 ± 13 for cycle 24 on the assumption that this cycle began in April 2007.