SOME COMMENTS ON THE PROBLEM OF SOLAR-CYCLE PREDICTION

The paper provides a number of regression equations that can be used to calculate the height of the odd Wolf number cycle. The feasibility of the rule of Gnevyshev-Ohl is analyzed as applied to the geomagnetic aa-index. A modified rule of Gnevyshev-Ohl has been formulated to describe the behaviour of aa-indices. A new method is suggested for early prediction of the next solar cycle. In this method, the angular coefficient (straightline slope) of linear dependence of aa-indices on the Wolf number at the descending branch of the cycle has been used as a prediction index. It is shown to a high degree of certainty that the new prediction index is related to the height of the forthcoming cycle. While the methods based on the ratio of the even-odd cycles in a pair give very high values of cycle 23 maximum (203.2 +/- 10.7), our new index, on the contrary, gives very low values (74.7 +/- 6.9). There are some contradictory symptoms indicating that the forthcoming cycle 23 is likely to violate the regularities established for the past 125 years.