Asian Basic and Applied Research Journal

The Forbush effect describes a sudden decrease in cosmic ray intensity on Earth, usually associated with solar storms like coronal mass ejections (CMEs) or solar flares. These events create shock waves that compress the Earth's magnetosphere, reducing cosmic ray influx. Interplanetary disturbances, caused by solar activities, can interact with Earth's magnetosphere, leading to geomagnetic storms associated with the Forbush effect. This study investigates the statistical relationship between the Forbush Effect and various interplanetary disturbance (FIED) parameters from 1957 to 2019. The parameters analyzed include  ABz_max , Kp_max , KT_min , KT_max , Be_max, Be_min, Ma_gn, A_xym' A_pmax' Bz_min' Az_range and SSN. The dataset, which includes 7482 events, was divided into subsets based on the type of Forbush Decrease (FD): Type 1 (1469) events), Type 2 (34 events), Type 3 (246 events), and Type 9 (5733) events), with a primary focus on Type 1 and Type 9 FD. Between 1957 and the 1980s,  values consistently remained around -6 to -7, indicating a predominantly southward orientation; however, post-1986, these values became more variable, with a range from -3.8 to -6.7 observed between 2010 and 2019. The  values varied from 2.6 nT to 9.6 nT during the late 1960s to the early 1980s, shifted to a range of 6.0 nT to 9.8 nT between 1986 and 2010, and after 2010, they ranged from 4.9 nT to 6.8 nT, including an unusual negative value of -4.8 nT in 2010. Peaks in  were particularly noticeable during the years 1971, 1972, 1975, 1976, the late 1980s, and 1995-1997, with an outlier occurring in 2009. Mean  values fluctuated significantly, with peaks observed in 1966, followed by a minimum in 2014, while mean  values showed low variability until a significant spike in 1986, followed by a sharp decline in 2014, after which they remained consistently low. mean values, which peaked in the late 1950s and early 1960s, reached a high of 68.3 in 1960 before declining to 18.0 in 1965; subsequent fluctuations continued through the 1970s and 1980s, with a low of 4.0 in 1986, and post-1986 values varied between 15-50, generally decreasing to 18.1 by 2019. values typically ranged from 4.0 to 5.0, with significant spikes in 1986 (44.6) and 2010 (55.3), indicating intense geomagnetic events.  values remained relatively stable between 1.0 and 1.6, except for significant spikes in 1986 (59.4) and 2010 (21.4).  mean values ranged between 1.2 to 1.5, with periodic spikes and dips. In general, Type 1 events exhibited considerable variability with irregular fluctuations, lacking a clear trend, while Type 9 events displayed more stable behavior with minor fluctuations, demonstrating a consistent and predictable pattern. Across all parameters, consistent trends were observed, with Type 1 and Type 9 events differing primarily in the strength of the correlations. Our analytical approach included descriptive statistics such as distribution plots, central tendency estimations (mean and median), and time series plots to identify annual patterns. Additionally, correlation analyses were conducted to elucidate relationships among the parameters. This extended analysis aims to provide deeper insights into the mechanisms linking interplanetary disturbances with cosmic ray modulation, offering implications for space weather prediction and our understanding of solar-terrestrial interactions.