Forbush Depression at Oulu in January 2026: Significant Galactic Cosmic Ray Decrease During Solar Cycle 25 Storm
Abstract: Coronal Mass Ejections (CMEs) and interplanetary shocks are examples of solar transient occurrences that substantially affect Galactic Cosmic Rays (GCRs). This study examined abrupt drops in cosmic ray strength using pressure-corrected hourly neutron monitor data from the Oulu Cosmic Ray Station for January 2026. On January 19?20, 2026, there was a notable and abrupt drop in cosmic ray counts, which suggests a classical Forbush Decrease (FD) event. After a sharp decline from about 5600 imp/min to about 4445 imp/min, the cosmic ray intensity gradually recovered over a few days. A substantial interplanetary disturbance that is probably connected to a CME-driven shock is confirmed by the computed FD amplitude. This study shows how solar activity and cosmic ray modulation are coupled throughout Solar Cycle 25.
Keywords: Forbush Decrease, Cosmic Rays, Oulu Neutron Monitor, Solar Cycle 25, CME, Space Weather
How to Cite?: Dr. Preeti Pandey, "Forbush Depression at Oulu in January 2026: Significant Galactic Cosmic Ray Decrease During Solar Cycle 25 Storm", Volume 15 Issue 2, February 2026, International Journal of Science and Research (IJSR), Pages: 1179-1182, https://www.ijsr.net/getabstract.php?paperid=SR26220000632, DOI: https://dx.doi.org/10.21275/SR26220000632