Enhancement for bitwise identical reproducibility of Earth system modeling on the C-Coupler platform

Abstract. Reliable numerical simulation plays a critical role in climate change study. The reliability includes bitwise identical reproducibility, i.e. bitwise identical result of numerical simulation can be reproduced. It is important to Earth system modeling and has already been used intra modeling groups for the model development. However, it is rarely considered in a wider range even worldwide. To help achieve the worldwide bitwise identical reproducibility, we introduce the detailed implementations for the bitwise identical reproducibility on the Community Coupler (C-Coupler) platform, a uniform runtime software environment that configures, builds and runs the models in the same manner. Moreover, we share a series of experiences and suggestions regarding the bitwise identical reproducibility. We believe that these implementations, experiences and suggestions can be easily extended to other model software platforms and can prospectively advance the model development and scientific researches in the future.