Fig. 3

Global mapping of the brightness locations of all of the orbital observations, grouped by the season: The sequence of the seasons is as follows: a Feb.–Apr. 2007, b May–Jul. 2007, c Aug.–Oct. 2007, d Nov. 2007–Jan. 2008, e Feb.–Apr. 2008, f May–Jul. 2008, and g Aug.–Oct. 2008. Single-peaked events are shown as red circles, and double-peaked events are shown as solid blue triangles and green squares. The dotted lines indicate the geomagnetic equator, and the solid lines at 0° latitude correspond to the geographic equator