Sunspot numbers, cosmic rays, and ozone variability: Correlation and wavelet analysis for mid-latitudes

This study investigates the intricate relationships between Total Ozone Content (TOC) and solar activity indicators, including Sunspot Number (SSN) and Cosmic Ray (CR) flux, across 11 Middle Eastern stations (18.22°N–39.94°N) over the period 1979–2022. Employing correlation and wavelet analyses, the research provides robust evidence of significant associations between TOC and solar phenomena, with positive correlations observed for TOC-SSN (R = 0.37to R = 0.50) and negative correlations for TOC-CR (R = −0.37 to R = −0.44). Seasonal variations were pronounced, with the strongest correlations during summer.

Wavelet analysis identified dominant periodicities, including an annual cycle (1-year) reflecting seasonal ozone variations, sub-annual periodicities (3–6 months) with geographic dependence, and inter-annual periodicities (2–4 years) linked to the Quasi-Biennial Oscillation (QBO) and El Niño-Southern Oscillation (ENSO). Coherence wavelet spectra demonstrated robust annual coherence across all stations, solar cycle coherence (4–8 years) in northern and central stations, and intermittent short-term periodicities (0.25–0.5 years). Coherence patterns exhibited latitudinal dependence, with stronger solar cycle coherence in northern stations and more variable patterns in southern stations, and were temporally modulated by solar activity phases, being stronger during solar maxima.

These findings underscore the critical influence of solar phenomena on ozone variability, advancing our understanding of atmospheric dynamics and their implications for climate and environmental systems.