Figure 4From: The spatial density gradient of galactic cosmic rays and its solar cycle variation observed with the Global Muon Detector Network Long-term variation of λ ∥ G r derived from the GMDN data. Yearly mean value and its error are deduced from the average and dispersion of monthly mean values. Gray vertical stripes indicate periods when the polarity reversal of the solar polar magnetic field (referred as A>0 or A<0) is in progress.Back to article page