TITLE:
Solar Modulation of Galactic Cosmic Rays and Its Impact on Global Methane Variability
AUTHORS:
Chijioke Onyia, Chukwujekwu Nworah Ofodum, Henry Onyedikachi Ezugwu, Uju Sonia Akubue, Monday Abonyi Ugwuanyi, Mercy H. Ezenwugo, Ngozi Dyian Ugwuozor, Emeka Michael Madike, Nnamdi M. Ezeoyili, Nnamdi Mellitus Agbo, Okolo Obinna, Kwenyeluchi Jennifer Oluka, Chimezie Bright Abugu, Chioma Jecinta Ani, Chidimma Juliet Nwachukwu, Chinwendu Sandra Osita-Okoh, Bonaventure I. Okere
KEYWORDS:
Galactic Cosmic Rays, Atmospheric Methane, Solar Modulation, Neutron Monitor, Correlation, Detrended Analysis, Solar Cycle, Station Dependent Response, Atmospheric Chemistry
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.16 No.3,
May
29,
2026
ABSTRACT: This study investigates the statistical relationship between solar-modulated galactic cosmic ray (GCR) flux and atmospheric methane (CH4) variability across a multi-altitude network of neutron monitor stations over a 20-year period (2006-2025). Monthly GCR intensity data from three stations spanning a broad altitude range: LMKS at Lomnicky ?tít, Slovakia at 2634 m (high altitude), MXCO at Mexico City, Mexico at 2240 m (mid altitude), and OULU at Oulu, Finland at 15 m (low altitude) were correlated with globally averaged atmospheric methane concentrations from the NOAA Global Monitoring Laboratory using Pearson and Spearman rank correlation coefficients computed via the SciPy statistical library. Raw correlations were statistically significant at all three stations, with LMKS exhibiting a positive association (r = +0.345, p