Fig. 6.From: Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquakeTime and ground range variations of (a) Doppler velocity and (b) echo power on beam 4. Data with echo power higher than 20 dB are displayed. Echoes within dotted gray rectangles are contaminated by 2-hop echoes (see Fig. 5). Propagation velocity of each disturbance shown in (a) is overlaid in (b).Back to article page