Neutron monitor data from two pairs of cosmic ray stations, Kiel/Tsumeb and Climax/Huancayo, are used to study the rigidity dependence of solar modulation during the solar activity cycle 22. The long-term decreases of cosmic ray intensity during the ascending phase of cycle 22 is characterized by the same rigitidy dependence as for the long-term recovery during the descending phase of cycle 21. This is equivalent to a lack of any significant spectral hysteresis in cosmic ray modulation for both half cycles surrounding the 1987 cosmic ray maximum. The above is true at least for 27-day averages of cosmic ray intensity and at neutron monitor rigidities. In December 1988 the first large Forbush decrease of cycle 22 marked the beginning of increased solar activity which resulted in several prominent interplanetary shocks in 1989--1991. These strong heliospheric disturbances produced global merged interaction regions (GMIRs) which were responsible for large step decreases in cosmic ray intensity seen at all spacecraft throughout the helisophere, including Voyager 2, Pioneer 10 and 11, as well as Voyager 1. It was found that in the neutron monitor rigidity range, such decreases were followed by rigidity-dependent recoveries. The rigidity-dependent recovery manifests itself by formation of hysteresis loops on correlation plots for low-versus high-rigidity cosmic ray intensity changes.

The loops, if completed, close approximately at the modulation level from which the corresponding step decrease started. On the other hand, the current long-term cosmic ray recovery (starting from Bartels solar rotation 2162) follows the ''normal'' rigidity dependence characteristic of both the A>0 recoveries and A0 are two different phases of the solar magnetic cycle). All this together confirms the bimodal character of cosmic ray modulation for 1985--1992, the same as found previously for cycles 19--21; the transient modulation (T≂0.5 to ~1 year) related to GMIRs is accompanied on recovery by the phenomenon of hysteresis, while the long-term modulation (T>1 year) is hysteresis free. The two explanations of the phenomenon of spectral hysteresis proposed in the literature, i.e., a time-dependent modulation via convection, diffusion, and drift effects and an acceleration of a normal cosmic ray spectrum in multiple shocks in the outer heliosphere (as proposed by Stoker and Moraal (1986)), are discussed in the context of the presented cosmic ray data.