Multirate time integration methods and their application for coupled atmosphere-ocean models

Abstract

In this thesis, various problems for coupled atmosphere-ocean models, in particular time integration schemes utilizing different time scales, are discussed. The different characteristics of the time integration schemes commonly applied in atmosphere and ocean models shall also be conserved for coupled models. The structure of the prognostic model equations allows the application of additive split integration schemes with different time scales. Two classes, the “Multirate Infinitesimal Step methods” and “Multirate Generalized Additive Runge—Kutta methods for N components”, are introduced and analysed. Furthermore, the problems investigated in the development of the coupled model ICONGETM are described in a more general sense and analysed for simplified coupled atmosphere-ocean models. The application of multirate methods for coupled models is demonstrated and discussed with benchmark examples for atmosphere and ocean models.