Thermodynamics Parameter Identification And Numerical Simulation In Arctic Sea Ice Temperature Field

With the background of the question of Arctic sea ice heat conduction, this dissertation establishes one-dimension and three-dimension heat conduction equations with initial boundary conditions respectively. On basis of the observed data, this paper constructs thermodynamics parameter models about thermodynamics parameters of sea ice in one-dimension Arctic sea ice temperature field and thermodynamics parameters of sea ice and sea water in three-dimension Arctic sea ice temperature field, respectively. By using the theory of identification and optimal control of distributed parameter systems, .it studies identification problems, presents optimal algorithm and implements numerical simulation to the given temperature fields by the optimal parameters.The main contributions are as follows:1. From the temperature of Arctic snow, sea ice and sea water, this dissertation ignores heat conduction in horizontal direction, considers temperature variations in vertical directions only, and establishes the multi-domain coupled system of one-dimension Arctic sea ice temperature field. It establishes the so-called output least square parameter identification model about the thermodynamics parameters of sea ice (heat storage capacity, density and conductivity) by using the so-called output least-square estimate, on basis of the observed data. By the theory of optimal control, the uniqueness and continuity of weak solution of this coupled system is described, and the identifiability of this parameter identification model is discussed in this dissertation. It proposes necessary optimality condition, constructs the optimal algorithm of identification model and obtains the optimal thermodynamic parameters of sea ice from the ice floe. Then, the numerical simulation is realized, and the numerical results of temperature distribution of Arctic sea ice are showed in this dissertation.2. By considering temperature variations in three directions including longitude direction, latitude direction and depth direction synthetically, this dissertation establishes the multi-domain coupled system of three-dimension Arctic sea ice temperature field and also considers the influence of ocean tidal current. On basis of the observed data, it establishes the parameter identification model about the thermodynamics parameters of sea ice and sea water (heat storage capacity and density) by using the so-called output least-square estimate also. This dissertation describes the uniqueness and continuity of weak solution of this coupled system, and discusses the identifiability of this parameter identification model. It proposes optimal algorithm, and realizes the numerical simulation to the temperature distributing of part of Arctic sea. In this dissertation, an effective method is proposed to determine the open boundary conditions of ocean tidal current, and the semi-implicit finite difference scheme to solve heat conduction equations is introduced seriously.