Solar Activity with respect to Ca-Plages

Abstract

Analysis of Ca-plage areas obtained from Kodaikanal K₂₃₂ spectroheliograms has been extended to 1977 for two solar cycles 19 and 20).The correlation of Ca-plage areas with other solar parameters, viz. relative sunspot numbers, sunspot areas, prominence areas and faculae areas has been obtained. Indices similar to Baur index which is based on faculae areas have been prepared separately with Ca-plage areas and prominence areas; and they have been compared with Baur index. These indices are interrelated and an index based on one parameter may be used in the absence of any other index.