An ACE/CRIS-observation-based Galactic Cosmic Rays heavy nuclei spectra model II

An observation-based Galactic Cosmic Ray (GCR) spectral model for heavy nuclei is developed. Zhao and Qin [J. Geophys. Res. Space Phys. 118, 1837 (2013)] proposed an empirical elemental GCR spectra model for nuclear charge 5 ≤ z ≤ 28 over the energy range ~30 to 500 MeV/nuc, which is proved to be successful in predicting yearly averaged GCR heavy nuclei spectra. Based on the latest highly statistically precise measurements from ACE/CRIS, a further elemental GCR model with monthly averaged spectra is presented. The model can reproduce the past and predict the future GCR intensity monthly by correlating model parameters with the continuous sunspot number (SSN) record. The effects of solar activity on GCR modulation are considered separately for odd and even solar cycles. Compared with other comprehensive GCR models, our modeling results are satisfyingly consistent with the GCR spectral measurements from ACE/SIS and IMP-8, and have comparable prediction accuracy as the Badhwar & O’Neill 2014 model. A detailed error analysis is also provided. Finally, the GCR carbon and iron nuclei fluxes for the subsequent two solar cycles (SC 25 and 26) are predicted and they show a potential trend in reduced flux amplitude, which is suspected to be relevant to possible weak solar cycles.