.png){kind=icon}
返回
Implicit and explicit cross-correlations in coupled data assimilation
.png){kind=icon}
PRE
AI
DOI：10.1002/qj.3373.png)
.png){kind=icon}
原文求助.png){kind=icon}
分享.png){kind=icon}
收藏
摘要
En 中文
The European Centre for Medium-Range Weather Forecasts has recently developed an implicit coupling approach in the coupled atmosphere-ocean assimilation (CERA) system, where atmospheric 4D-Var and ocean 3D-Var are synchronized using multiple outer iterations in the incremental variational formulation. Since this original work on outer-loop coupling, it has been unclear just how closely the CERA system with implicit coupled covariances approximates a strongly coupled data assimilation with ensemble-based coupled covariances. A series of single-observation experiments in a perfect twin framework has been conducted to evaluate the effectiveness and efficiency of outer-loop coupling and the amplitude of the implicit cross-correlations between atmospheric and ocean temperature. They are compared against a coupled assimilation system that specifies cross-correlations explicitly from an ensemble of coupled forecasts. We find that both the implicit outer-loop and explicit ensemble-based methods produce equally skilful estimates of the coupled state in the middle of a 24hr assimilation window. Our estimates of the rate of outer-loop convergence suggest that atmospheric and ocean states synchronize within the first 6-10hr of the assimilation window. We conclude that outer-loop coupling is effective when the window is long enough that original imbalances in the atmospheric and ocean increments can synchronize within the length of the assimilation window. On the other hand, we suggest that explicit coupling is preferable for data assimilation systems with short assimilation windows (e.g. 6hr or less).
Keyword:
coupled assimilation
cross-correlation
ensemble
outer-loop coupling
AI总结
对已上传原文的论文进行重点信息的提取，主要内容包括：简要概述、研究摘要、背景介绍、关键亮点、图文解析、展望与总结。
期刊
IF:
2.9
论文数:
5.8K
被引数:
2.4W
机构
引用论文
.png){kind=icon}
分享收藏分享收藏
查看更多内容