Application of regional meteorology and air quality models based on MIPS CPU Platform

Abstract

Abstract. The MIPS processor architecture is a type of Reduced Instruction Set Computing (RISC) processor architecture, which has advantages in terms of energy consumption and efficiency. There are few studies on the application of MIPS CPUs in the geoscientific numerical models. In this study, Loongson 3A4000 CPU platform with MIPS64 architecture was used to establish the runtime environment for the air quality modelling system WRF-CAMx in Beijing-Tianjin-Hebei region. The results show that the relative errors for the major species (NO2, SO2, O3, CO, PNO3 and PSO4) between the MIPS and X86 benchmark platform are within ± 0.1 %. The maximum Mean Absolute Error (MAE) of major species ranged to 10−2 ppbV or μg m−3, the maximum Root Mean Square Error (RMSE) ranged to 10−1 ppbV or μg m−3, and the Mean Absolute Percentage Error (MAPE) remained within 0.5 %. The CAMx takes about 15.2 minutes on Loongson 3A4000 CPU and 4.8 minutes on Intel Xeon E5-2697 v4 CPU, when simulating a 2h-case with four parallel processes using MPICH. As a result, the single-core computing capability of Loongson 3A4000 CPU for the WRF-CAMx modeling system is about one-third of Intel Xeon E5-2697 v4 CPU, but the thermal design power (TDP) of Loongson 3A4000 is 30W, only about one-fifth of Intel Xeon E5-2697 v4, which TDP is 145W. Thus, Loongson 3A4000 has higher energy efficiency in the application of the WRF-CAMx modeling system. The results also verify the feasibility of cross-platform porting and the scientific usability of the ported model. This study provides a technical foundation for the porting and optimization of numerical models based on MIPS or other RISC platforms.