Atmospheric ozone modulation by cosmic ray Forbush decreases: Patterns and anomalies across multiple stations

Abstract

This investigation systematically examines the effects of 13 Forbush Decrease (FD) events on the total ozone column (TOC) and ozone concentrations within six stratospheric layers (L6–L11). The primary aim is to quantify the magnitude, temporal dynamics, and latitudinal variability of ozone responses to FD-driven CR perturbations. Using superposed epoch analysis, ozone data from 18 globally distributed stations (spanning 55.8°N to −6.2°N) were analyzed over a 21-day window centered on each FD event, with deviations calculated relative to a 4-day pre-FD baseline (days −4 to −1). Results reveal a distinct latitudinal gradient in ozone responses: high-latitude stations (e.g., Moscow, 55.8°N; Copenhagen, 55.7°N) exhibit rapid and substantial increases in TOC (5–15 %, peaking within 3–4 days) and layer-specific ozone concentrations (e.g., L6: 8–16 % by days 3–4; L11: 3–10 % by days 0–4), attributed to CR-induced ionization processes. Conversely, low-latitude stations (e.g., Jakarta, −6.2°N; Hanoi, 21.0°N) show subdued and delayed responses (TOC: 1–6 %; layers: 1–5 %, peaking by days 5–8), likely due to photochemical suppression and enhanced atmospheric mixing. Vertical analysis highlights more pronounced CR-driven effects in the lower stratosphere (e.g., L6), with greater variability in the upper layers (e.g., L11), indicating altitudinal differences in ozone sensitivity to CR flux variations. These findings emphasize the pivotal role of CR flux reductions in influencing stratospheric ozone dynamics, with broader implications for atmospheric chemistry, radiative forcing, and climate systems. The results underscore the necessity for further mechanistic investigations and advanced coupled chemistry-climate modeling to deepen our understanding of these intricate solar-terrestrial interactions.