ABSTRACT

In this study, moist singular vector (MSV) was developed based on GRAPES-GEPS (Global/Regional Assimilation and Prediction System – Global Ensemble Prediction System), the adjoint model of large-scale condensation and cumulus deep convection in GRAPES-4DVar (Four-dimensional variational assimilation). Five consecutive days of numerical experiments were performed for a preliminary evaluation of MSV. The singular values, horizontal distribution structure, spread of MSVs perturbation and its influence on the ensemble prediction were compared for each group of tests. The results showed that in the middle and high latitudes of the northern and southern hemispheres, the addition of both linearized moist physical processes increased the spread of the mid- and low-level SVs, but the linearized large-scale condensation (LC) process plays a leading role in the structure of MSV. The analysis of ensemble forecast shows the inclusion of moist linearized physical processes led to a greater effect of MSV on the rainfall levels of 10 and 25 mm and a slight improvement in anomaly correlation coefficient (ACC) of the atmospheric circulation field, and more obvious improvement due to linearized large-scale condensation. In the future, continuous multi-year testing and tropical-specific analyses are required for operation.

摘要

在这项研究中，基于 GRAPES-GEPS（全球/区域同化和预测系统 - 全球集合预测系统）开发了湿奇异矢量（MSV），GRAPES-4DVar（四-维度变分同化）。连续五天的数值实验对 MSV 进行了初步评估。比较了各组试验的奇异值、水平分布结构、MSV扰动分布及其对集合预测的影响。结果表明，在北半球和南半球的中高纬度地区，两种线性化湿润物理过程的加入增加了中低层SV的传播，但线性化大规模冷凝（LC）过程在MSV的结构中起着主导作用。集合预报分析表明，湿线性化物理过程的加入导致MSV对10和25 mm降水量的影响更大，大气环流场距平相关系数（ACC）略有改善，改善更明显由于线性化大规模凝结。未来，运行需要持续的多年测试和热带特定分析。并且由于线性化的大规模冷凝而得到更明显的改善。未来，运行需要持续的多年测试和热带特定分析。并且由于线性化的大规模冷凝而得到更明显的改善。未来，运行需要持续的多年测试和热带特定分析。