Space Climate
Open Access

Fig. 5.


Download original image

Annual numbers of storms (storm days) of different Gosling et al. (1991) sizes from 1932, the beginning of the Kp index, to 2011 (top panel) and similarly for NOAA G storm sizes (third panel). The second panel shows the yearly sunspot number (vertical lines indicate years of sunspot maximum), while the bottom panel shows the number of G storms/solar cycle. Note that the persistent low levels of storm activity during the recent solar minimum are unprecedented during this 80-year period. In particular, 2008–2011 had the lowest number of small or G1 storms recorded in the Kp index based on this analysis.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.