A Study of Coupling Parameter Estimation Implemented by 4D-Var and EnKF with a Simple Coupled System

Coupling parameter estimation (CPE) that uses observations to estimate the parameters in a coupled model through error covariance between variables residing in different media may increase the consistency of estimated parameters in an air-sea coupled system. However, it is very challenging to accura...

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Bibliographic Details
Main Authors: Guijun Han, Xinrong Wu, Shaoqing Zhang, Zhengyu Liu, Ionel Michael Navon, Wei Li
Format: Article
Language:English
Published: Wiley 2015-01-01
Series:Advances in Meteorology
Online Access:http://dx.doi.org/10.1155/2015/530764
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Summary:Coupling parameter estimation (CPE) that uses observations to estimate the parameters in a coupled model through error covariance between variables residing in different media may increase the consistency of estimated parameters in an air-sea coupled system. However, it is very challenging to accurately evaluate the error covariance between such variables due to the different characteristic time scales at which flows vary in different media. With a simple Lorenz-atmosphere and slab ocean coupled system that characterizes the interaction of two-timescale media in a coupled “climate” system, this study explores feasibility of the CPE with four-dimensional variational analysis and ensemble Kalman filter within a perfect observing system simulation experiment framework. It is found that both algorithms can improve the representation of air-sea coupling processes through CPE compared to state estimation only. These simple model studies provide some insights when parameter estimation is implemented with a coupled general circulation model for improving climate estimation and prediction initialization.
ISSN:1687-9309
1687-9317