Figure 3.

(a) Median Neutral Gas and Ion Mass Spectrometer (NGIMS) ${\text{CO}}_2^{+}$ ion density altitude profiles, calculated using data from latitudes poleward of 30°S and solar zenith angles less than 90°, and five different longitude ranges: 20–40°E (black), 60–80°E (blue), 160–180°E (dark green), 180–200°E (light green), and 320–340°E (red). The dashed lines show upper and lower quartiles for data at 60–80°E (weak crustal fields) and 160–180^◦E (strong crustal fields). (b) As panel (a) but for NGIMS ${\text{O}}_2^{+}$ ion density. (c) As panel (a) but for NGIMS O⁺ ion density. (d) As panel (a) but for NGIMS total ion density.