Open Access
Research Article

Fig. 7

image

Download original image

Analysis of the sensitivity of the Hartland (HAD) station. Time-of-day (UT)/time-of-year (F) plots of: (left column) the modelled sensitivity for the am index, Sam, for the current stations and sector weighting functions; (middle column) modelled values of the ratio sHAD/Sam where sHAD is the sensitivity of the Hartland magnetometer station for measuring its aK values, aHAD; and (right column) means of the observed values of the ratio 〈aHAD〉/〈am〉 = sHAD/Sam. All data are for eight UT bins 3 h wide and 20 F bins 18.25 days wide over the years 1959–2017 (inclusive). The panels are for am ranges (from top to bottom) of: am ≥ 70 nT; 60 ≤ am < 110 nT; 50 ≤ am < 90 nT; 40 ≤ am < 60 nT; 30 ≤ am < 50 nT; 20 ≤ am < 40 nT; 10 ≤ am < 20 nT; and 0 ≤ am < 10 nT shown in Figure 6. The modelled values are based on the mean am in each band which equals, respectively, 109.14, 75.94, 63.56, 47.76, 37.71 27.50, 13.96, and 5.32 nT. Modelled sensitivities are computed at points 1 h apart in UT and 1/365 apart in F and then averaged into the same sized UT-F bins (3 h by 0.05) as used for the observations. Note that the left-hand plots are colour-contoured using the 0.8–1.2 scale given by the lower colour bar while the modelled and observed sHAD/Sam sensitivity ratios both use the 0.5–1.6 scale given by the upper colour bar. In all plots unity values are coloured yellow.

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.