Reply on RC2

Abstract. Although the Singular Value Decomposition-three Dimensional Ensemble Variational (SVD-3DEnVar) data assimilation scheme has achieved successful application in real case simulations with comprehensive numerical weather prediction models, its computational efficiency still cannot meet the demands of actual operational numerical forecasting. The main limitations lie in the generation of three-dimensional perturbations and the implementation of parallel calculations. This paper constructed a three-dimensional perturbation field generation scheme that supports multi-process parallelism and can directly generate any specified number of grid points in both horizontal and vertical directions. At the same time, an efficient parallel implementation scheme has been developed according to the characteristics of local patch assimilation in the SVD-3DEnVar scheme. The Observing System Simulation Experiment (OSSE) test results based on the Tropical Regional Atmospheric Model System (TRAMS) show that after computational efficiency optimization, the time required to generate a 3D perturbation field has been reduced from 22 minutes to 2.2 seconds, while the runtime of the assimilation process has decreased from 1,700 minutes under serial execution to less than 15 minutes (using 150 nodes in parallel). Finally, we conducted an assimilation experiment using actual observational data of sea surface wind fields to preliminarily validate the reasonableness of the assimilation results from the optimized SVD-3DEnVar scheme.