Vertical velocity (m/day) from HyCOM GoM, time-averaged June 10, 2018, through July 19, 2018, and depth-averaged between 5 m and 50 m, or bottom when less than 50 m. The 50-m isobath is shown in blue; the polygon used for initial trajectory positions, and a representative trajectory, (see Fig. \ref{581122}) are shown in black