Climax GCR counts & aa-index

GCR counts from Climax (red) and the aa-index (blue). The straight lines show the best linear-fit against time estimated through linear regression. The GCR measurements are shown in solid black line, from which a trend of -180 +/- 253 counts/decade is estimated, and this is associated with a p-value (the probability of this being different to the null-hypothesis: zero trend) of 0.477 (not statistically significant at the 5% level). The aa-index is represented by the blue line, and the corresponding trend of 1.5 +/- 0.4/decade is associated with a p-value of 0.0002 (highly statistically significant). A regression analysis points to a clear link between GCR and the aa-index, and the analysis of variance yields R2 = 0.1466 and the p-value= 0. The yellow line shows the global mean temperature from CRU for comparison. [Data source: http://ulysses.uchicago.edu/NeutronMonitor/neutron_mon.html" , "http://www.cru.uea.ac.uk/cru/data/temperature/" and "ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA'].