State estimates and forecasts of the loop current in the Gulf of Mexico using the MITgcm and its adjoint

Handle URI:
http://hdl.handle.net/10754/552202
Title:
State estimates and forecasts of the loop current in the Gulf of Mexico using the MITgcm and its adjoint
Authors:
Gopalakrishnan, Ganesh; Cornuelle, Bruce D.; Hoteit, Ibrahim ( 0000-0002-3751-4393 ) ; Rudnick, Daniel L.; Owens, W. Brechner
Abstract:
An ocean state estimate has been developed for the Gulf of Mexico (GoM) using the MIT general circulation model and its adjoint. The estimate has been tested by forecasting loop current (LC) evolution and eddy shedding in the GoM. The adjoint (or four-dimensional variational) method was used to match the model evolution to observations by adjusting model temperature and salinity initial conditions, open boundary conditions, and atmospheric forcing fields. The model was fit to satellite-derived along-track sea surface height, separated into temporal mean and anomalies, and gridded sea surface temperature for 2 month periods. The optimized state at the end of the assimilation period was used to initialize the forecast for 2 months. Forecasts explore practical LC predictability and provide a cross-validation test of the state estimate by comparing it to independent future observations. The model forecast was tested for several LC eddy separation events, including Eddy Franklin in May 2010 during the deepwater horizon oil spill disaster in the GoM. The forecast used monthly climatological open boundary conditions, atmospheric forcing, and run-off fluxes. The model performance was evaluated by computing model-observation root-mean-square difference (rmsd) during both the hindcast and forecast periods. The rmsd metrics for the forecast generally outperformed persistence (keeping the initial state fixed) and reference (forecast initialized using assimilated Hybrid Coordinate Ocean Model 1/12° global analysis) model simulations during LC eddy separation events for a period of 1̃2 months.
KAUST Department:
Earth Science and Engineering Program
Citation:
State estimates and forecasts of the loop current in the Gulf of Mexico using the MITgcm and its adjoint 2013, 118 (7):3292 Journal of Geophysical Research: Oceans
Journal:
Journal of Geophysical Research: Oceans
Issue Date:
Jul-2013
DOI:
10.1002/jgrc.20239
Type:
Article
ISSN:
21699275
Additional Links:
http://doi.wiley.com/10.1002/jgrc.20239
Appears in Collections:
Articles; Earth Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorGopalakrishnan, Ganeshen
dc.contributor.authorCornuelle, Bruce D.en
dc.contributor.authorHoteit, Ibrahimen
dc.contributor.authorRudnick, Daniel L.en
dc.contributor.authorOwens, W. Brechneren
dc.date.accessioned2015-05-04T16:40:55Zen
dc.date.available2015-05-04T16:40:55Zen
dc.date.issued2013-07en
dc.identifier.citationState estimates and forecasts of the loop current in the Gulf of Mexico using the MITgcm and its adjoint 2013, 118 (7):3292 Journal of Geophysical Research: Oceansen
dc.identifier.issn21699275en
dc.identifier.doi10.1002/jgrc.20239en
dc.identifier.urihttp://hdl.handle.net/10754/552202en
dc.description.abstractAn ocean state estimate has been developed for the Gulf of Mexico (GoM) using the MIT general circulation model and its adjoint. The estimate has been tested by forecasting loop current (LC) evolution and eddy shedding in the GoM. The adjoint (or four-dimensional variational) method was used to match the model evolution to observations by adjusting model temperature and salinity initial conditions, open boundary conditions, and atmospheric forcing fields. The model was fit to satellite-derived along-track sea surface height, separated into temporal mean and anomalies, and gridded sea surface temperature for 2 month periods. The optimized state at the end of the assimilation period was used to initialize the forecast for 2 months. Forecasts explore practical LC predictability and provide a cross-validation test of the state estimate by comparing it to independent future observations. The model forecast was tested for several LC eddy separation events, including Eddy Franklin in May 2010 during the deepwater horizon oil spill disaster in the GoM. The forecast used monthly climatological open boundary conditions, atmospheric forcing, and run-off fluxes. The model performance was evaluated by computing model-observation root-mean-square difference (rmsd) during both the hindcast and forecast periods. The rmsd metrics for the forecast generally outperformed persistence (keeping the initial state fixed) and reference (forecast initialized using assimilated Hybrid Coordinate Ocean Model 1/12° global analysis) model simulations during LC eddy separation events for a period of 1̃2 months.en
dc.relation.urlhttp://doi.wiley.com/10.1002/jgrc.20239en
dc.rightsArchived with thanks to Journal of Geophysical Research: Oceansen
dc.titleState estimates and forecasts of the loop current in the Gulf of Mexico using the MITgcm and its adjointen
dc.typeArticleen
dc.contributor.departmentEarth Science and Engineering Programen
dc.identifier.journalJournal of Geophysical Research: Oceansen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionClimate, Atmospheric Science and Physical Oceanography; Scripps Institution of Oceanography; La Jolla, San Diego California USAen
dc.contributor.institutionClimate, Atmospheric Science and Physical Oceanography; Scripps Institution of Oceanography; La Jolla, San Diego California USAen
dc.contributor.institutionMarine Physical Laboratory; Scripps Institution of Oceanography; La Jolla California USAen
dc.contributor.institutionPhysical Oceanography; Woods Hole Oceanographic Institution; Woods Hole Massachusetts USAen
kaust.authorHoteit, Ibrahimen
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