Abstract The aim of this research work is to investigate the association of Forbush decreases with solar and interplanetary features i.e. sunspot number, solar radio flux, solar wind speed, solar plasma temperature, solar plasma density, interplanetary magnetic field for solar cycles 23 and 24. We have also taken Ap, Kp, Dst, as a geomagnetic index. A Chree analysis by the superposed epoch method has been done for the study. The current analysis depicts that various solar and interplanetary factor such as VSP, DST and Kp are CR-effective. The CRI is found to be good correlated with these parameters for both solar cycles. During solar cycle 24, the solar and interplanetary parameters sunspot number (Rz), SRF, and Ap had good values of correlation coefficient with CRI; nevertheless, the correlation coefficient for Rz and Ap was moderate, and the correlation coefficient for SRF was weak. In both solar cycles, the TSP and CRI have a moderate correlation, while DSP and CRI have a poor correlation in solar cycle 24 and a good correlation in soar cycle 23. Additionally, we found that, compared to solar cycle 24, solar cycle 23 had a stronger relationship with CRI. We also looked into the possibility that, during solar cycle 24, there is a difference in the way Rz and SRF behave with CRI. We have proven statistically that a variety of solar and interplanetary factors are important factors to produce cosmic ray decreases.
Kumar et al. (2025) studied this question.