Scientific design and preliminary results of three-dimensional variational data assimilation system of GRAPES
Scientific design and preliminary results of three-dimensional variational data assimilation system of GRAPES
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DOI：
10.1007/s11434-008-0416-0
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发表时间：
2008-11
影响因子：
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通讯作者：
J. Xue;S. Zhuang;G. Zhu;Hua Zhang;Zhiquan Liu;Yan Liu;Zhaorong Zhuang
中科院分区：
文献类型：
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作者：
J. Xue;S. Zhuang;G. Zhu;Hua Zhang;Zhiquan Liu;Yan Liu;Zhaorong Zhuang
本文介绍了中国气象局最近研制的全球-区域预报同化系统（GRAPES）资料同化部分的科学设计和初步结果。这是一个建立在全球和区域网格上的三维变分同化系统，有利于直接同化天基遥感数据，并与GRAPES预报模式框架相匹配。假设状态变量分解为平衡和不平衡分量。通过引入一个简单的转换从状态变量到控制变量的递归或频谱滤波器，迭代的收敛速度大大加快的3DVAR的成本函数的最小化。动力平衡的定义取决于所考虑的环流的特征尺度。平衡部分与不平衡部分的比率由规定的背景误差统计控制。理想化的试验产生与解析解相同的结果。真实的数据案例研究的结果表明，该系统的能力，以改善分析相比，传统的计划。最后，对系统的进一步开发进行了讨论。
The scientific design and preliminary results of the data assimilation component of the Global-Regional Prediction and Assimilation System (GRAPES) recently developed in China Meteorological Administration (CMA) are presented in this paper. This is a three-dimensional variational (3DVar) assimilation system set up on global and regional grid meshes favorable for direct assimilation of the space-based remote sensing data and matching the frame work of the prediction model GRAPES. The state variables are assumed to decompose balanced and unbalanced components. By introducing a simple transformation from the state variables to the control variables with a recursive or spectral filter, the convergence rate of iteration for minimization of the cost function in 3DVar is greatly accelerated. The definition of dynamical balance depends on the characteristic scale of the circulation considered. The ratio of the balanced to the unbalanced parts is controlled by the prescribed statistics of background errors. Idealized trials produce the same results as the analytic solution. The results of real data case studies show the capability of the system to improve analysis compared to the traditional schemes. Finally, further development of the system is discussed.