Temporal variability of galactic cosmic ray intensity and its dependence on various solar parameters observed during solar cycles 23 and 24

In this study, we have investigated the solar modulation of galactic cosmic rays (GCRs) during solar cycles 23 and 24. The periods comprise two epochs of negative and positive polarities of the heliospheric magnetic field from the Sun's North Polar Region. We have used concurrent solar and interplanetary magnetic field data, the tilt angle of the heliospheric current sheet (HCS), and the cosmic ray data as the inputs to obtain the required results. During these two cycles, we have investigated the relationship between simultaneous fluctuations in cosmic ray intensity and solar/interplanetary parameters as obtained by some previous researchers. We have noticed several unusual aspects in cosmic ray modulation, including a high GCRs intensity in SC24 compared with the previous solar cycle. The Pearson's correlation of GCRs intensity with considered solar parameters is r GCRs vs SSN (- 0.79) in SC 23 and (- 0.91) in SC 24, r GCRs vs F10.7 (- 0.88) in SC23 and (- 0.87) in SC 24. The relationships of GCRs intensity with interplanetary parameters also are strongly anticorrelated except for IMF (Bz) in solar cycle 24 and solar wind speed in both cycles. The Pearson's correlation of GCRs intensity and interplanetary parameters is r GCRs vs IMF (- 0.73) in SC23 and (- 0.46) in SC 24, r GCRs vs HCS (- 0.77) in SC 23 and (- 0.87) in SC 24. We also have used time lag and Spearman's correlation coefficient to determine the monotonicity of GCRs intensity and solar/interplanetary characteristics. Thus, we have concluded that the intensity of GCRs has inverse relationships and has been significantly impacted by solar and interplanetary parameters with time lag over both solar cycles 23 and 24.