Ice Drift

the movement of ice at sea by winds and currents.

Numerous observations of drifting ice in the Arctic Ocean have shown that the velocity of the drift depends on wind velocity and, over longer periods, on the velocity of the relatively slow but steadier surface currents. The deflecting force of the earth’s rotation causes a deviation whereby ice drifts in a direction to the right of the direction of the wind in arctic latitudes and to the left of the direction of the wind in antarctic latitudes. On the average, this deviation is close to 30°, decreasing with an increase in wind velocity and increasing when the wind is less strong. The wind coefficient (the ratio of drift velocity to wind velocity) is close to 0.02. Because of friction, ice that is drifting under the influence of the wind carries the closest surrounding water along with it. Changes in the velocity and direction of the wind may sharply (in the course of several hours) alter a previously established pattern in the ice drift. The proximity of continental shorelines, the presence of islands and shallows, and the nature of the relief of the ocean floor all have a significant influence on the direction of the drift.