Fig. 10From: Statistical analysis of ionospheric mid-latitude trough over the Northern Hemisphere derived from GPS total electron content dataThe MLT variation of the trough depth (left panel), background TEC (middle panel), and TEC value at the trough minimum (right panel) during different seasons. The red, black, and blue lines denote the results for summer, winter, and equinox seasons, respectively. The median and the upper and lower quartiles of these parameters are shown for each 1Â h interval of MLTBack to article page