Local-density-based analysis on characteristics of traffic flow in Tiaozhoumen Channel of Ningbo Zhoushan Port

The attributes of the spatial distribution（ship type, ship position, ship speed, traffic density） and the time characteristics（traffic change against time, daily traffic change） of the traffic flow in Tiaozhoumen Channel is studied by means of local density and mathematical statistics. The research shows the following facts: The geographic position of docks and main channel decide the traffic distribution, and ships are highly concentrated in deeper water area; The number of larger ships in a day is twice to three times of that of smaller ships; 69.35% of larger ships are cargo ships and smaller ships are mostly workboats, accounting for 40.34%; The ships in the channel usually sail at medium or low speed, especially cargo ships and tanks; Container ships, workboats and passenger ships may sail at higher speed; Small ships usually follow the rule of "to start work when the sun rises and to stop work when the sun sets", so the number of small ships in the channel changes significantly over time of the day. In the contrary, the number of larger ships does not change too much in a day.