ASPECTS OF THE LONG-TERM COSMIC-RAY MODULATION .1. SOLAR-CYCLE ASCENDING PHASES AND ASSOCIATED GREEN CORONA FEATURES

To investigate the long-term modulation of galactic cosmic rays at the ground-based detector energies, the monthly values of the neutron mon itor (Climax, Mt. Washington, Deep River, and Huancayo) and ionization chamber (Cheltenham/Fredericksburg, Huancayo, and Yakutsk) intensitie s have been correlated with the sunspot numbers (used as a proxy index for transient solar activity) for each phase-of sunspot cycles 18 to 22. Systematic differences are found for results concerning odd and ev en sunspot cycles. During odd cycles (19 and. 21) the onset time of co smic-ray modulation is delayed when compared with the onset time of th e sunspot cycle, while they are more similar during even (18, 20, and 22) cycles. Checking the green corona data, on a half-year basis, we f ound typical heliolatitudinal differences during ascending phases of c onsecutive sunspot cycles. This finding suggests a significant role of the latitudinal coronal behaviour in the heliospherical dynamics duri ng a Hale cycle. Such effectiveness concerns not only the transient in terplanetary-perturbations but also the recurrent ones. In fact, when lag between cosmic-lay data and sunspot numbers is considered, the ant icorrelation between both parameters is very high (correlation coeffic ient \r\ > 0.9) for all the phases considered, except for the declinin g ones of cycles 20 and 21, when high-speed solar wind streams coming from coronal holes affect the cosmic-ray propagation, and the Rz param eter is no longer the right proxy index for solar-induced effects in t he interplanetary medium.