What determines the observational magnitudes of Forbush events on Earth: A critique of the traditional manual method

Forbush decreases (FDs) seem to be the compass for researchers searching for Sun–Earth weather relationships. Thus, a wide range of the solar-terrestrial literature is dominated by FD-based analyses. While the results of such investigations are often questioned on the basis of small FD sample sizes, statistical significance tests and inappropriate methodological approaches, the efficiency and the validity of manual FD event selection are yet to be examined in detail. Because the results obtained depend on the Forbush event location on Earth, and on timing and magnitude estimation, this paper emphasizes the need for the correct acquisition of FD data prior to composition or correlation/regression analyses.