Assessment of an ensemble system that assimilates Jason-1/Envisat altimeter data in a probabilistic model of the North Atlantic ocean circulation

Abstract : A realistic circulation model of the North Atlantic ocean at 0.25° resolution (NATL025 NEMO configuration) has been adapted to explicitly simulate model uncertainties. This is achieved by introducing stochastic perturbations in the equation of state to represent the effect of unresolved scales on the model dynamics. The main motivation for this work is to develop ensemble data assimilation methods, assimilating altimetric data from past missions Jason-1 and Envisat. The assimilation experiment is designed to provide a description of the uncertainty associated with the Gulf Stream circulation for years 2005/2006, focusing on frontal regions which are predominantly affected by unresolved dynamical scales. An ensemble based on such stochastic perturbations is first produced and evaluated using along-track altimetry observations. Then each ensemble member is updated by a square root algorithm based on the SEEK (singular evolutive extended Kalman) filter (Brasseur and Verron, 2006). These three elements – stochastic parameterization, ensemble simulation and 4-D observation operator – are then used together to perform a 4-D analysis of along-track altimetry over 10-day windows. Finally, the results of this experiment are objectively evaluated using the standard probabilistic approach developed for meteorological applications (Toth et al., 2003; Candille et al., 2007).
Document type :
Journal articles
Complete list of metadatas

Cited literature [38 references]  Display  Hide  Download

https://hal-insu.archives-ouvertes.fr/insu-01203709
Contributor : Bérénice Boeuf <>
Submitted on : Wednesday, September 23, 2015 - 3:58:27 PM
Last modification on : Monday, September 2, 2019 - 2:46:05 PM
Long-term archiving on : Tuesday, December 29, 2015 - 9:39:22 AM

File

OCEAN SCIENCE - Assessment of ...
Publisher files allowed on an open archive

Identifiers

Collections

Citation

Guillem Candille, Jean-Michel Brankart, Pierre Brasseur. Assessment of an ensemble system that assimilates Jason-1/Envisat altimeter data in a probabilistic model of the North Atlantic ocean circulation. Ocean Science, European Geosciences Union, 2015, 11 (3), pp.425-438. ⟨10.5194/os-11-425-2015⟩. ⟨insu-01203709⟩

Share

Metrics

Record views

173

Files downloads

261