Numerical Simulation And Parameter Identification Of The Temperature Field In The Nonlinear System Of The Sea Ice

This dissertation, based on practical background of researching the Artic sea ice,.Takes the classical sea-ice model to describe the thermodynamic field of sea-ice. The thermodynamic parameters of sea-ice temperature system are taken as control variables, establishes a parabolic distributed system and optimal control system of the thermodynamic processes of the Arctic sea-ice. The aim for researching the Arctic sea ice is that the terminal output of this dynamical system will best approximate the corresponding values of the measured points. Based on the nonlinear dynamic system, taking the aim mentioned above as the performance index, a optimal control system of the Arctic sea ice is established. The present dissertation intends to study the optimal control system, construct a global optimisation algorithm, and applies the algorithm into the practical research of sea ice.Chapter 1 reviews the progress of control theory, and includes many achievements by scholars home and abroad in the field of researching the Arctic sea ice. Chapter 2 mainly discusses some basic knowledge, including some conceptions and properties of parabolic distributed parameter systems and its optimal algorithm which serves as the preparation of the proceeding research. Chapter 3 and Chapter 4 present the main study results of this dissertation, which can be summarized as follows:1. The basic principle of uniform design and optimal algorithm is discussed here, and the superiority of uniform design in searching the global optimal algorithm and the scarcity of the classical Hooke-Jeeves algorithm was discussed combine the practical problem of this dissertation.The impoved Hooke-Jeeves algorithm was constructed, the numerical results illustrate the better convergence of the impoved Hooke-Jeeves than the classical Hooke-Jeeves algorithm.2. Establish a nonlinear dynamic system and its optimal control system, the unique existence of the solution of the2 state equations and the existence of optimal solutions of the optimal control system are discussed.3. Half implicit difference scheme and a improved Hooke-Jeeves algorithm are proposed and worked out by C++ language. The numerical results illustrate the validity and efficiency of the algorithms.