Distribution of coronal holes over the solar surface 1970--1991

The latest catalogue of coronal holes (hereinafter CHs) was analysed to find long-term and large-scale regularities in the latitudinal and longitudinal distributions of this phenomenon.A systematic displacement of the CHs frequency curves and different trends of this displacement were found when analysing the CHs according to their size and helio-latitude. The longitudinal distribution of the CHs shows two very flat maxima, and the global changes of the area covered by coronal holes are discussed in relation to the 11-year solar cycle. The analogy of the CHs latitudinal and longitudinal distributions with that of the green corona low brightness regions (hereinafter GCLBRs) is indicated and physically substantiated.