Open Access
Research Article

Fig. 9

image

Download original image

Scatter of fraction of auroral electrojet disturbance indices exceeding the 95-percentile in each year, as a function of the annual mean value for that year for (a) AU and (b) AL. The analysis is of hourly means so f[AU > AUo] is the fraction of strong substorm growth- and expansion-phase hours defined by AU > AUo and so are in the top 5% of all observed values. Similarly f[AL<ALo] is the fraction of strong substorm expansion phases defined by AL < ALo. The 95 percentiles are defined from the distributions of all available hourly means over the interval 1967–2016 (inclusive) and are AUo = 228 nT and ALo = −444 nT. The AE index, AE = AU − AL shows the same behaviour and is discussed further below.

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.