The curve shown in the graph (dH/dT)sa (sa - South America) represents the average of the time derivative of the H component of all stations used in the calculation. The gray region around the curve represents the standard deviation of each point. Use the tool at the bottom of the chart to filter the data ranges for curve details.

The curve shown in the graph ΔHsa represents the average of ΔH each station of of EMBRACE Magnetometer Network. The ΔH is calculated by the difference between the average of the five quietest days of last month (according Q-International Days and D-Days, Kyoto) and the H component of each season. The gray region around the curve represents the standard deviation of each point. Use the tool at the bottom of the chart to filter the data ranges for curve details.