Coupled data assimilation(CDA)is a powerful strategy for integrating observations with coupled numerical models.This strategy holds great potential for enhancing weather and climate reanalysis and prediction.How to ad...Coupled data assimilation(CDA)is a powerful strategy for integrating observations with coupled numerical models.This strategy holds great potential for enhancing weather and climate reanalysis and prediction.How to address crossscale interactions in CDA is an important issue.In particular,the cross-scale interactions in the strongly coupled data assimilation(SCDA)framework pose substantial challenges.In this study,increasing the state estimation accuracy using an ensemble adjustment Kalman filter based on the two-scale Lorenz’96(tsL96)model is investigated.Using the SCDA framework,we adopt cross-component localization factors and several covariance inflation schemes to address the filter divergence problem.The results show that ensembles of an appropriate size can achieve good assimilation results,the optimal localization parameters are scale-dependent for the model variables,and the adaptive inflation scheme outperforms the static fixed and relaxation-to-prior spread schemes.Although these experiments were carried out using an ideal framework,this study provides a valuable reference for improving estimation accuracy with the SCDA framework in operational simulation and prediction models.展开更多
基金The fund from Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.SML2021SP314the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,under contract No.JG2406+1 种基金the National Natural Science Foundation of China under contract No.42476196the Natural Science Foundation of Shanghai under contract No.24ZR1420100.
文摘Coupled data assimilation(CDA)is a powerful strategy for integrating observations with coupled numerical models.This strategy holds great potential for enhancing weather and climate reanalysis and prediction.How to address crossscale interactions in CDA is an important issue.In particular,the cross-scale interactions in the strongly coupled data assimilation(SCDA)framework pose substantial challenges.In this study,increasing the state estimation accuracy using an ensemble adjustment Kalman filter based on the two-scale Lorenz’96(tsL96)model is investigated.Using the SCDA framework,we adopt cross-component localization factors and several covariance inflation schemes to address the filter divergence problem.The results show that ensembles of an appropriate size can achieve good assimilation results,the optimal localization parameters are scale-dependent for the model variables,and the adaptive inflation scheme outperforms the static fixed and relaxation-to-prior spread schemes.Although these experiments were carried out using an ideal framework,this study provides a valuable reference for improving estimation accuracy with the SCDA framework in operational simulation and prediction models.
