Forbush Decrease（FD）指的是觀測到宇宙射線通量發生快速下降、再緩慢恢復的現象，而ICME事件被認為是引發FD事件的原因之一，雖然已經有不少相關的研究，然而至今仍有許多FD相關物理機制尚未被了解。 本研究參考許多目前已發表的研究成果，挑選1998年至2024年的62例完整觀測之ICME事件，分析其震波、鞘層與磁雲區段的物理參數對銀河宇宙射線（GCR）在FD事件中下降幅度A_FD的影響。根據WIND衛星的電漿與磁場資料，計算各區段磁場強度B、風速V、密度N、溫度T及電漿β值、以及計算磁雲磁場的時鐘角與錐角等參數。並搭配奧盧中子監測站計數率及京都世界地磁資料中心的SYM-H指數，分析其震波與鞘層和磁雲區間的物理參數、磁雲中的磁場旋轉情形、南向磁場的數值與持續時間、太陽週期對FD現象的影響。 本篇研究結果中，鞘層在B、V、T與A_FD具正相關，磁雲則在B、V與A_FD具正相關，磁雲旋轉的時鐘角在不同A_FD區間有不同的分布情形，南向磁場持續時間與A_FD無明顯相關，另外每年FD事件數與太陽黑子數變化趨勢相近。本研究整理了一份橫跨較長時間的事件列表、並分析不同因素對FD事件的影響，供想研究FD相關內容的學者參考。;Forbush Decrease (FD) refers to the phenomenon whereby galactic cosmic ray flux is observed to rapidly decrease and then slowly recover. ICME events are considered one of the causes triggering FD events. Although considerable related research has been conducted， many physical mechanisms related to FD remain not yet understood. This study references numerous published research findings and selected 62 observed ICME events from 1998 to 2024， analyzing the influence of physical parameters in their shock， sheath， and magnetic cloud regions on the decrease amplitude A_FD of galactic cosmic rays (GCR) during FD events. Based on plasma and magnetic field data from the WIND spacecraft， we calculated magnetic field strength B， wind speed V， density N， temperature T， and plasma β values for each region， as well as the clock angle and cone angle parameters of the magnetic cloud magnetic field. Combined with the Oulu neutron monitor count rate monitoring station and SYM-H index from the Kyoto World Data Center for Geomagnetism， we analyzed the physical parameters of shock， sheath， and magnetic cloud regions， magnetic field rotation patterns within magnetic clouds， southward magnetic field values and duration， and the influence of solar cycle on FD phenomena. The research results show that in the sheath region， B， V， and T exhibit positive correlation with A_FD， while in the magnetic cloud， B and V exhibit positive correlation with A_FD. The clock angle of magnetic cloud rotation shows different distribution patterns in different A_FD intervals， southward magnetic field duration shows no obvious correlation with A_FD， and the annual number of FD events shows similar variation trends to sunspot numbers. This study compiled an event catalog spanning a relatively long time period and analyzed the influence of different factors on FD events， providing reference for scholars wishing to study FD-related content.
