Impact of correlated observation errors on the conditioning of variational data assimilation problems

O Goux, S Gürol, AT Weaver… - … Linear Algebra with …, 2024 - Wiley Online Library
An important class of nonlinear weighted least‐squares problems arises from the
assimilation of observations in atmospheric and ocean models. In variational data …

Anisotropic diffusion filters for flow-dependent variational data assimilation of sea surface temperature

Y Hu, X Zhang, D Li, W Li, L Zhang, H Fu, L Zhang - Ocean Modelling, 2023 - Elsevier
It is well known that the background error covariance matrix in the data assimilation is
anisotropic and varied with the flow field, that is, flow-dependent. However, it is generally …

A new global ocean ensemble system at the Met Office: Assessing the impact of hybrid data assimilation and inflation settings

DJ Lea, J While, MJ Martin, A Weaver… - Quarterly Journal of …, 2022 - Wiley Online Library
We have developed a global ocean and sea‐ice ensemble forecasting system based on the
operational forecasting ocean assimilation model (FOAM) system run at the Met Office. The …

A new global daily sea‐surface temperature analysis system at Environment and Climate Change Canada

S Skachko, M Buehner, A Caya… - Quarterly Journal of …, 2024 - Wiley Online Library
A new global daily sea‐surface temperature (SST) analysis system has been developed at
Environment and Climate Change Canada (ECCC). All components of the new SST …

Impact of an Ensemble of Ocean Data Assimilations in ECMWF's next generation ocean reanalysis system

M Chrust, AT Weaver, P Browne, H Zuo… - arXiv preprint arXiv …, 2024 - arxiv.org
An Ensemble of Data Assimilations (EDA) can provide valuable information on the analysis
and short-range forecast uncertainties. The present ECMWF operational ocean analysis and …

Ocean data assimilation focusing on integral quantities characterizing observation profiles

N Sugiura, S Kouketsu, S Osafune - Frontiers in Marine Science, 2024 - frontiersin.org
An observation operator in data assimilation was formalized based on the signatures
extracted from the integral quantities contained within observed vertical profiles in the …

Analytical four-dimensional ensemble variational data assimilation for joint state and parameter estimation

K Liang, W Li, G Han, Y Gong, S Liu - Atmosphere, 2022 - mdpi.com
The joint state and parameter estimation problem is an important issue in data assimilation.
An adjoint free data assimilation method, namely analytical four-dimensional ensemble …

A filtered multilevel Monte Carlo method for estimating the expectation of discretized random fields

J Briant, P Mycek, M Destouches, O Goux… - arXiv preprint arXiv …, 2023 - arxiv.org
We investigate the use of multilevel Monte Carlo (MLMC) methods for estimating the
expectation of discretized random fields. Specifically, we consider a setting in which the …

Application of the finite analytic numerical method to a flow-dependent variational data assimilation

Y Hu, W Li, X Zhang, G Liu, L Zhang - Acta Oceanologica Sinica, 2024 - Springer
An anisotropic diffusion filter can be used to model a flow-dependent background error
covariance matrix, which can be achieved by solving the advection-diffusion equation …

Application of deep learning to the estimation of normalization coefficients in diffusion-based covariance models

FK Skrunes, M Destouches, A Weaver… - arXiv preprint arXiv …, 2023 - arxiv.org
Variational data assimilation in ocean models depends on the ability to model general
correlation operators in the presence of coastlines. Grid-point filters based on diffusion …