Ensemble Optimal Interpolation: multivariate properties in the Gulf of Mexico

François Counillon; Laurent Bertino

doi:10.1111/j.1600-0870.2008.00383.x

Ensemble Optimal Interpolation: multivariate properties in the Gulf of Mexico

Tellus

Volume 61 (2009): Issue 2

By: François Counillon and Laurent Bertino

Open Access

|Jan 2009

Abstract

High-resolution models can reproduce mesoscale dynamics and the variability in the Gulf of Mexico (GOM), but cannot provide accurate locations of currents without data assimilation (DA). We use the computationally cheap Ensemble Optimal Interpolation (EnOI) in conjunction with the Hybrid Coordinate Ocean Model (HYCOM) model for assimilating altimetry data. The covariance matrix extracted from a historical ensemble, is three-dimensional and multivariate. This study shows that the multivariate correlations with sea level anomaly are coherent with the known dynamics of the area at two locations: the central part of the GOM and the upper slope of the northern shelf. The correlations in the first location are suitable for an eddy forecasting system, but the correlations in the second location show some limitations due to seasonal variability. The multivariate relationships between variables are reasonably linear, as assumed by the EnOI. Our DA set-up produces little noise that is dampened within 2 d, when the model is pulled strongly towards observations. Part of it is caused by density perturbations in the isopycnal layers, or artificial caballing. The DA system is demonstrated for a realistic case of Loop Current eddy shedding, namely Eddy Yankee.

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DOI: https://doi.org/10.1111/j.1600-0870.2008.00383.x | Journal eISSN: 3035-9554

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Language: English

Page range: 296 - 308

Submitted on: Sep 26, 2007

Accepted on: Nov 18, 2008

Published on: Jan 1, 2009

Published by: Stockholm University Press

In partnership with: Paradigm Publishing Services

© 2009 François Counillon, Laurent Bertino, published by Stockholm University Press
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 61 (2009): Issue 2