Application of regional meteorology and air quality models based on the microprocessor without interlocked piped stages (MIPS) and LoongArch CPU platforms

Abstract

The microprocessor without interlocked piped stages (MIPS) and LoongArch are reduced instruction set computing (RISC) processor architectures, which have advantages in terms of energy consumption and efficiency. There are few studies on the application of MIPS and LoongArch central processing units (CPUs) in geoscientific numerical models. In this study, the Loongson 3A4000 CPU platform with the MIPS64 architecture and the Loongson 3A6000 CPU platform with the LoongArch architecture were used to establish the runtime environment for the air quality modelling system Weather Research and Forecasting-Comprehensive Air Quality Model with extensions (WRF-CAMx) in the Beijing-Tianjin-Hebei region. The results show that the relative errors for the major species (NO22, SO22, O23, CO, PNO23, and PSO24) between the MIPS and X86 benchmark platforms are within 2±0.1g2%. The maximum mean absolute error (MAE) of major species ranged up to 102-2g2ppbV or 2μgg2m2-3, the maximum root mean square error (RMSE) ranged up to 102-1g2ppbV or 2μgg2m2-3, and the mean absolute percentage error (MAPE) remained within 0.5g2%. The CAMx takes about 195g2min on the Loongson 3A4000g2CPU, 71g2min on the Loongson 3A6000g2CPU, and 66g2min on the Intel Xeon E5-2697 v4 CPU, when simulating a 24g2h case with four parallel processes using MPICH. As a result, the single-core computing capability of the Loongson 3A4000 CPU for the WRF-CAMx modelling system is about one-Third of the Intel Xeon E5-2697 v4 CPU, and the one of Loongson 3A6000g2CPU is slightly lower than that of Intel Xeon E5-2697 v4 CPU; but, the thermal design power (TDP) of Loongson 3A4000 is 40g2W, while the TDP of Loongson 3A6000 is 38g2W, only about one-fourth of that of Intel Xeon E5-2697 v4, whose TDP is 145g2W. 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, LoongArch, or other RISC platforms.