Time evolutions of sea surface elevation for different ocean current velocities. (a) C0 = −1.5 m·s−1; (b) C0 = −1.0 m·s−1; (c) C0 = −0.5 m·s−1; (d) C0 = 0 m·s−1; (e) C0 = 0.5 m·s−1; (f) C0 = 1.0 m·s−1; (g) C0 = 1.5 m·s−1.