Types of sunspots, magnetic classification and flare yield in cycle no. 20

The yield of flare activity and some other characteristics were investigated in the years 1965 to 1976 with regard to the types of sunspot groups of the Zurich and magnetic classifications. The groups in question were located at heliographic longitudes of +-70deg. The flare yield was also determined for the individual Zurich types regardless of the magnetic type, on the one hand, and for the magnetic types regardless of the Zurich type on the other. The flare yield was investigated also by Zurich types and magnetic classification in the course of the years of the cycle. For the flare yield of spotgroups it was found that in the course of cycle No. 20 the variation of flare yields was not related to the variation of the sunspot number R. The largest flare yield was displayed by the F and E types and by the magnetic delta and γ-types. A number of other results concerning the occurrence of single types of spot groups was also obtained that agreed well with earlier findings. (author)