Developments in observing system technologies and ocean data assimilation (DA) are
symbiotic. New observation types lead to new DA methods and new DA methods, such as …

This article presents coupled data assimilation (DA) activities at the European Centre for
Medium‐Range Weather Forecasts (ECMWF). Coupled DA is an essential component of the …

A coupled atmosphere–ocean data assimilation system, the Meteorological Research
Institute‐Coupled Data Assimilation System Version 1 (MRI‐CDA1), was developed based …

The standard, strong‐constraint formulation of 4D‐Var is designed to correct for random,
zero‐mean errors from the model forecast and the observations. However, significant …

Data assimilation (DA) experiments are performed to assess impacts of observations in
climate model state estimation through the cross-domain ocean–atmosphere forecast error …

Developing effective ways to model and cycle the background‐error covariance matrix is an
active area of research in data assimilation. An important aspect of this problem when using …

There is growing awareness that errors in the model equations cannot be ignored in data
assimilation methods such as four‐dimensional variational assimilation (4D‐Var). If allowed …

Strongly coupled data assimilation allows observations of one Earth system component (eg,
the ocean) to directly update another component (eg, the atmosphere). The majority of the …

We assess a possibility to efficiently represent the strongly coupled increment in an ocean–
atmosphere coupled data assimilation (DA) system by applying an iterative procedure …

We examine data assimilation coupling between meteorology and chemistry in the
stratosphere from both weak and strong coupling strategies. The study was performed with …