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H.S. Ahluwalia (University of New Mexico, Dept of Physics and Astronomy)
Sometime ago a new solar frequency was discovered in the data of the planetary index Ap (1932-1997); namely the three-cycle quasiperiodicity in Ap minima, which typically occur one year after sunspot number (SSN) minima.It was found that the numerical value of Ap minima are linearly correlated with the amplitude of the smoothed SSN cycle (defined as the numeric difference between the maximum and the minimum SSN values). Based on the observed annual mean value of 8.5 for the Ap minimum in 1997 we predicted that cycle 23 will be moderate (a la cycle 17); its developmental timeline is predicted to be well below those for the most active cycles (18, 19, 21, 22) of the twentieth century. This forecast is in sharp contrast to an overly exuberant forecast that cycle 23 may, "potentially be one of the greatest cycles in recent times, if not the greatest." As of the end of February 2001, our forecast appears to be right on the mark.We shall review the solar, interplanetary, and geophysical data as of the end of May 2001 and describe important lessons learned from this experience.