Forecast of Maximum Sunspot Number of Cycle 24

Abstract

It is important for space weather to forecast the maximum sunspot number of the coming cycle. Sunspot number is an indicator of solar activity and occurrence of space storms increases in proportion to solar activity. We found that there is a negative correlation between occurrence number of no-spot days near solar minimum and maximum sunspot number of the next cycle. Using this relation, we made a forecast of the maximum sunspot number of Cycle 24. The maximum sunspot number of Cycle 24 is lower than that of Cycle 23 of 120.8 according to our forecast. Low solar activity of Cycle 24 is also suggested by low geomagnetic activity near minimum and long cycle length of Cycle 23.