Joint ECMWF/OceanPredict workshop on Advances in Ocean Data Assimilation

The second-order exact particle filter NETF (nonlinear ensemble transform filter) is combined with local ensemble transform Kalman filter (LETKF) to build a hybrid filter method (LKNETF). The filter combines the stability of the LETKF with the nonlinear properties of the NETF to obtain improved assimilation results for small ensemble sizes. Both filter components are localized in a consistent...

Variational data assimilation requires implementing the tangent-linear and adjoint (TA/AD) version of any operator. This intrinsically hampers the use of complicated observations. Here, we assess a new data-driven approach to assimilate acoustic underwater propagation measurements (Transmission Loss, TL) into a regional ocean forecasting system. TL measurements depend on the underlying sound...

The ocean forecasting community is recently devoting a growing effort towards the prediction of mesoscale processes at global scale. New high-resolution global simulation are able to resolve mesoscale structures in large part of the basin. On the other hand, a realistic representation of mesoscale variability is triggered by the capability of the assimilation schemes to efficiently ingest and...

This study describes the global Observing System Simulation Experiments (OSSE) system developed to assess the impact of the future Surface Water and Ocean Topography (SWOT) mission for global ocean analysis and prediction. The 1/12° global ocean circulation model and the data assimilation system (SAM2) are described. The data assimilation system differs from the one used operationally by...

Argo has revolutionised our understanding of ocean physics, and Biogeochemical-Argo (BGC-Argo) is now extending the concept to biogeochemistry. There are currently around 300 operational floats measuring one or more biogeochemical variable, and over the coming years an array of BGC-Argo floats will be established to provide regular profiles of oxygen, nitrate, pH, chlorophyll, suspended...

An operational system for the Arctic Ocean (above 60 degree North) biogeochemical reanalysis product is developed. The reanalysis data production is based on a fixed-lag ensemble Kalman smoother with joint state-parameter estimation and a physical-biogeochemical coupled ocean model cycled over eight day assimilation windows. Satellite chlorophyll-a and in-situ nutrients, nitrate, silicate and...

Satellite altimeter data have been assimilated into ocean models aiming at a better estimation of the current and past ocean state and thus leading more accurate predictions. In this study, we attempt to develop a regional and short-term ocean forecasting system, where the lateral boundary conditions are modified by assimilation of satellite sea surface height data by an approximate Kalman...

The Norwegian Climate Prediction Model version 1 (NorCPM1) is a new research tool for performing climate reanalyses and seasonal-to-decadal climate predictions. It has been used for contributing output to the Decadal Climate Prediction Project (DCPP) as part of the Climate Model Intercomparison Project phase 6 (CMIP6). It combines the Norwegian Earth System Model version 1 (NorESM1) with the...

Ocean reanalyses are becoming increasingly important to reconstruct and provide an overview of the ocean state from the past to the present-day. In the scope of the Copernicus Marine Environment Monitoring Service (CMEMS), a new Black Sea (BS) reanalysis, BS-REA (BSE3R1 system), has been produced by using an advanced variational data assimilation method to combine the best available...

The different mechanisms controlling the heat budget of the North Sea are investigated based on a combination of satellite sea surface temperature measurements and numerical model simulations. Lateral heat fluxes across the shelf edge and into the Baltic Sea are considered, as well as vertical ocean-atmosphere heat exchange. The 3DVAR data assimilation (DA) scheme is applied, which contains...

Ensemble Optimal Interpolation (EnOI) is used by several groups for ocean forecasting and reanalysis. Here, EnOI is applied to a gridded observational product – mapping Argo and satellite data to produce weekly analyses on a global 1/10 degree grid. Starting with a configuration that has long been applied under Bluelink for forecasting and reanalysis, many shortcomings quickly became evident....

The Ocean Model, Analysis and Prediction System (OceanMAPS) is the ocean forecasting system implemented at the Bureau of Meteorology. OceanMAPS provides 7-day forecasts on daily basis in near global eddy-resolving horizonal grid. The system is based on Modular Ocean Model (MOM 5) and data assimilation is using Enkf-C software in Ensemble Optimal Interpolation (EnOI) mode. An efficient,...

The newly developed coupled climate model "Icosahedral Nonhydrostatic Earth System Model" (ICON-ESM) has recently become available. The pre-industrial control run has a stable climate with closed energy and water budgets. The global mean temperature is 13.73°C and the Atlantic meridional overturning circulation at 26°N has a strength of 16 Sv. The ICON-ESM will serve for seasonal to decadal...

Ocean biogeochemical (BGC) models utilise a large number of poorly-constrained global parameters to mimic unresolved processes and reproduce the observed complex spatio-temporal patterns. Large model errors stem primarily from inaccuracies in these parameters whose optimal values can vary both in space and time. This study aims to demonstrate the ability of ensemble data assimilation (DA)...

We compare the results of strongly coupled data assimilation and weakly coupled data assimilation by analyzing the assimilation effect on the prediction of the ocean as well as the atmosphere variables. The AWI climate model (AWI-CM), which couples the ocean model FESOM and the atmospheric model ECHAM, is coupled with the parallel data assimilation framework (PDAF, http://pdaf.awi.de). The...

The ocean forecasting system (OFS) based on the surface wave-tide-circulation coupled ocean model developed by the First Institute of Oceanography (FIO-COM), Ministry of Natural Resources, China was started its operational running since May 2016. The ensemble adjustment Kalman filter (EAKF) is designed for this OFS to assimilate the near real time oceanic observations, including the sea...