Fig. 2From: Estimation of temporal and spatial variation of sound speed in ocean from GNSS-A measurements for observation using moored buoyOutline of conducted observation using vessel for six observational epochs. a Two-dimensional ship track maps. Pink squares and star symbols represent seafloor units and the point where observations for conductivity, temperature, and depth (CTD) were conducted. b The variation of sound speed in ocean along to the depth. c The sound speed perturbation calculated by Eq. (2)Back to article page