MP CBM-Z V1.0: design for a new CBM-Z gas-phase chemical mechanism architecture for next generation processors

Abstract. Precise and rapid air quality simulation and forecasting are limited by the computation performance of the air quality model, and the gas-phase chemistry module is the most time-consuming function in the air quality model. In this study, we designed a new framework for the widely used Carbon Bond Mechanism Z (CBM-Z) gas-phase chemical kinetics kernel to adapt the Single Instruction Multiple Data (SIMD) technology in the next-generation processors for improving its calculation performance. The optimization implements the fine-grain level parallelization of CBM-Z by improving its vectorization ability. Through constructing loops and integrating the main branches, e.g. diverse chemistry sub-schemes, multiple spatial points in the model can be operated simultaneously on vector processing units (VPU). The Intel Xeon E5-2697 V4 CPU and Intel Xeon Phi 7250 Knight Landing (KNL) are used as the benchmark processors. The validation of the model outputs indicates that the relative errors are in an acceptable range (