Fig. 3.From: Giant ionospheric disturbances observed with the SuperDARN Hokkaido HF radar and GPS network after the 2011 Tohoku earthquake(a) Time and ground range variations of Doppler velocity (with echo power higher than 10 dB) on beams 1–11. (b) Two-dimensional maps of Doppler velocity for four time periods. Beam 4 is marked in each figure.Back to article page