Dr Hathaway of NASA has revised his Cycle 24 sunspot forecast. He predicts a smoothed sunspot number maximum of about 60 in the Spring of next year. Cycle 24 will be the smallest in about 100 years. For the record, his forecast graphed is shown below:
He has revised his prediction method as follows:
Recent work [see Hathaway Solar Physics; 273, 221 (2011)] indicates that the equatorward drift of the sunspot latitudes as seen in the Butterfly Diagram follows a standard path for all cycles provided the dates are taken relative to a starting time determined by fitting the full cycle. Using data for the current sunspot cycle indicates a starting date of May of 2008. Fixing this date and then finding the cycle amplitude that best fits the sunspot number data yields the current (revised) prediction.
To read more of the NASA report click here.
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