Experiment evaluates ocean models and data assimiliation in the Gulf Stream

Willems, Robert; Glenn, Scott; Crowley, Michael F.; Malanotte‐Rizzoli, Paola; Young, Roberta E.; Ezer, Tal; Mellor, George L.; Arango, Hernan G.; Robinson, Allan R.; Lai, C.-C. A.

doi:10.1029/94eo01024

Cited by 21 publications

(10 citation statements)

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“…though no attempt has been made to use identical configurations and surface forcing. Such comparisons are to be found in other studies, which focus on large-scale processes [Gerdes, 1993], Gulf Stream dynamics [Willems et al, 1994], and coastal processes [Haidvogel and Beckman, 1997]. One finding of these and other studies is that a sigma coordinate ocean model is attractive for simulating processes associated with bottom topography such as flow over sills, continental shelf flows, tidal flows, and bottom boundary layers dynamics; thus sigma layer models have been widely used in studies of coastal regions.…”

Section: Introduction the Atlantic Ocean And Its Interaction With Thementioning

confidence: 95%

Simulations of the Atlantic Ocean with a free surface sigma coordinate ocean model

Ezer¹,

Mellor²

1997

J. Geophys. Res.

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Section: Introduction the Atlantic Ocean And Its Interaction With Thementioning

confidence: 95%

Simulations of the Atlantic Ocean with a free surface sigma coordinate ocean model

Ezer¹,

Mellor²

1997

J. Geophys. Res.

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“…The forecast was ‘blind’ in that, although the modelers assimilated satellite data to initialize the forecast, they had no prior knowledge of EddyWatch frontal positions. This procedure is different from previous evaluations of forecast models [e.g., Ezer et al , 1992; Willems et al , 1994] which were all initialized with, and then compared against, the same observation dataset.…”

Section: Introductionmentioning

confidence: 99%

An exercise in forecasting loop current and eddy frontal positions in the Gulf of Mexico

Oey

Ezer

Forristall

et al. 2005

Geophysical Research Letters

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[1] As part of a model-evaluation exercise to forecast Loop Current and Loop Current eddy frontal positions in the Gulf of Mexico, the Princeton Regional Ocean Forecast System (PROFS) is tested to forecast 14 4-week periods Aug/25/99 -Sep/20/00, during which a powerful eddy, Eddy Juggernaut (Eddy-J) separated from the Loop Current and propagated southwestward. To initialize each forecast, PROFS assimilates satellite sea surface height (SSH) anomaly and temperature (SST) by projecting them into subsurface density using a surface/subsurface correlation that is a function of the satellite SSH anomaly. The closest distances of the forecast fronts from seven fixed stations in the northern Gulf over a 4-week forecast horizon are then compared against frontal observations derived primarily from drifters. Model forecasts beat persistence and the major source of error is found to be due to the initial hindcast fields.

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“…The data is projected on a 0.2Њ ϫ 0.2Њ horizontal grid and 34 vertical levels. The OTIS model has been run at the Center for Ocean and Atmospheric Modeling (COAM) of the University of Southern Mississippi using high quality data prepared especially for the Data Assimilation and Model Evaluation Experiments (DA-MEEs) (Willems et al 1994).…”

Section: B the Otis Analysis Datamentioning

confidence: 99%

Data Assimilation Experiments in the Gulf Stream Region: How Useful Are Satellite-Derived Surface Data for Nowcasting the Subsurface Fields?

Ezer¹,

Mellor²

1997

J. Atmos. Oceanic Technol.

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Satellite-derived surface data have become an important source of information for studies of the Gulf Stream system. The question of just how useful these datasets are for nowcasting the subsurface thermal fields, however, remains to be fully explored. Three types of surface data-sea surface temperature (SST), sea surface height (SSH), and Gulf Stream position (GSP)-are used here in a series of data assimilation experiments to test their usefulness when assimilated into a realistic primitive equation model. The U.S. Navy's analysis fields from the Optimal Thermal Interpolation System are used to simulate the surface data and to evaluate nowcast errors. Correlation factors between variations of the surface data and variations of the subsurface temperature are used to project the surface information into the deep ocean, using data and model error estimates and an optimal interpolation approach to blend model and observed fields. While assimilation of each surface data source shows some skill in nowcasting the subsurface fields (i.e., reducing errors compared to a control case without assimilation), SSH data reduce errors more effectively in middepths (around 500 m), and SST data reduce errors more effectively in the upper layers (above 100 m). Assimilation of GSP is effective in nowcasting the deep Gulf Stream, while the model dynamics produce eddies that are not included in the GSP analysis. An attempt to optimally combine SST and SSH data in the assimilation shows an improved skill at all depths compared to assimilation of each set of data separately.

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Experiment evaluates ocean models and data assimiliation in the Gulf Stream

Cited by 21 publications

References 0 publications

Simulations of the Atlantic Ocean with a free surface sigma coordinate ocean model

Simulations of the Atlantic Ocean with a free surface sigma coordinate ocean model

An exercise in forecasting loop current and eddy frontal positions in the Gulf of Mexico

Data Assimilation Experiments in the Gulf Stream Region: How Useful Are Satellite-Derived Surface Data for Nowcasting the Subsurface Fields?

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