LONGITUDINAL AND TEMPORAL VARIATIONS OF SUNSPOT REGIONS AND CORONAL HOLES DURING CYCLE-21

The relationship between sunspot activity in heliographic longitude and coronal holes is investigated for the period corresponding to Cycle 21 (Carrington rotations 1623-1779). The major result is that, based on He i 10830 Å data, a strong inverse association is found between the longitudinal positions of sunspot groups and the size and number of coronal holes (especially, the equatorial extensions of polar holes). Frequencies of coincidences in longitude were determined for both types of activity and the evolution of coronal holes over Cycle 21 is depicted in the form of a 'butterfly diagram' displaying their latitudinal and longitudinal extents. A tabular listing identifies average longitude and persistence of sunspot active longitudes. © 1990 Kluwer Academic Publishers.