Characterization Of Drift Particles' Density Within Search Areas Based On The Cloud Theory And Field Theory

Along with reform and opening-up, China's economic activity is becoming more frequency and water shipping is tasked for huge amount transportation t. To ensure the safety of life at sea, it is shall to study the subject of maritime search and rescue firstly. So, provide a model for the drifts which can support basis of drift the theory and suggestion in search and rescue operations is what many countries' researchers are doing.The facts of drift movement are reviewed and learned, main contain wind and flow, by reading the study given by our predecessors. In order to reduce the difficulty of establish model, wind-driven current is contained in water current field. The main effect of wind-driven current is focused on current's speed rate. Drift path is determined by the vector. At the same time, monte carlo method is used for launching and tracking drift particles.After learning search information systems have been used in shipping developed countries, such as Canada, Britain, the United States, and France. It is suggested that based on cloud model'uncertainty expression and knowledge of data field'expression whole domain areas, potential field of drift particles which represent position of possible distribution is analysised within the search areas. It is found by computer simulation that factor of uncertainty is the key of result. Different emphases are seen by modifying the factor of uncertainty that determine the effect size of uncertainty function. When factor of uncertainty is enough small, a clear characterization of particle density can been given in region with dense drift particles. Meanwhile, particle density characterization for whole search areas is good given, when the factor of uncertainty is get a fitter number. According to the different step size it is fount that field calculation results is no different from the results without the use of cloud model when grid step size too rough. Only the grid step length is small enough which means detailed environmental parameters, cloud model and data calculation combining can show characteristic adequately. In consideration of the frequency of cross wind direction sign changes, simulating experiment obtained a "dumbbell" search area after 6 hours the drift beganMatlab system can figure upon the field quickly which provide suggestion in search and rescue mission.