Title: Parameter estimation with the augmented Lagrangian method for a parabolic equation Author: Trygve K. Nilssen and Xue--Cheng Tai Abstract: In this paper, we investigate the numerical identification of the diffusion parameters in parabolic problems. The identification is formulated as a constrained minimization problem. By using the augmented Lagrangian method, the inverse problem is reduced to a coupled nonlinear algebraic system, which can be solved efficiently with the preconditioned conjugate gradient method. Finally, we present some numerical experiments to show the efficiency of the proposed method, even for identifying highly discontinuous parameters.