Ice Drift – movement of ice generated by wind and water streams. I. D. of the Arctic Ocean is caused mainly by wind, but in long periods of time (months) due to great violation of wind speed and directions, I. D. is determined by permanent currents. The main elements of the large-scale I. D. (as well as surface water circulation) are trans-Arctic I. D. in the eastern part of the hemisphere and the anticyclonic in the western part. The trans-Arctic I. D. originates in the north of the Chukchi Sea, then following to the area of the geographical pole and further to the strait between Greenland and Spitsbergen. In half a year, a block of ice within a drift passes about 400–450 km in the general direction. In the anticyclonic circular drift, the ice makes a full clockwise rotation in 5–10 years.