P.F.J. Lermusiaux, P.J. Haley, Jr.,
W.G. Leslie, A. Phadnis,
M.P. Ueckermann, C. Mirabito
Nicholas Makris, Dick K.P Yue
Massachusetts Institute of Technology
Ongoing MIT research
Additional IODA links
MSEAS IODA supported publications
|This research sponsored by the Office of Naval Research|
Ongoing MIT research
Long-Term Goal: Study the coupled dynamics of ocean, surface and internal waves, seabed and acoustics processes with atmospheric forcing, integrating our ocean-wave-acoustic fields and models, including computational codes. The specific goals are to:
- Utilize large-scale nonlinear direct simulations to improve understanding, study and discover fundamental dynamics
- Validate and further develop statistical and stochastic models of such dynamics, using guidance from the direct deterministic simulations and from sea measurements
Research group roles:
- Makris group: new unified four-dimensional modeling with a focus on fundamental acoustic research, including 3D spatial multiple scattering effects and their statistical representations
- Yue group: computational and modeling research for novel large-scale deterministic/phase-resolved predictions of nonlinear ocean waves and flow fields, including surface gravity waves, internal waves and bottom bathymetry interactions
- Lermusiaux group: multi-resolution data-assimilative ocean modeling for acoustic studies including new stochastic process parameterizations and study of ocean dynamics most relevant for acoustics, from internal tides and waves to mesoscales
Shallow Water 2006 (SW06) Re-Analysis
A data-driven re-analysis of SW06 has recently been carried out by the Lermusiaux MSEAS group. In this re-analysis a number of areas have been addressed : improved initial and boundary conditions and feature models (FM) (see below); the vertical discretization now consists of 100 optimized vertical levels; atmospheric forcing now includes improved E-P and direct fluxes from WRF/NOGAPS; updated OTIS tidal forcing; data assimilation is weaker and more frequent with shorter space scales; and model parameters of vertical mixing (wind mixing, PP background mixing), horizontal mixing and bottom friction have been re-evaluated.
An important compenent of the re-analysis was the significant improvement of the model initial and boundary conditions. This was achieved through the inclusion of additional synoptic data (WODB, GTSPP) and pseudo profiles to bolster the shelf-break front; correcting the WOA climatology for the slope to match the 2006 conditions; better defining the shelfbreak T/S front FM (steepness and location of foot); improving the Gulf Stream T/S FM based on synoptic data; and, utilizing transport feature models for the Gulf Stream, slope recirculation gyre and shelfbreak front. Data processing of the data was also improved (extending shallow profiles to the surface; improved deep WOA climatology; corrected SST). The time dependent boundary conditions were also updated to permit better radiation of outgoing waves.
Model output files from the best simulation of the SW06 conditions can be found here.
|May 2013||Updated time dependent BCs for better radiation; Improved merging WRF & NOGAPS atmospheric forcing; Jan 2013 OTIS Tides||Dec 2012||2011 OTIS Tides; Tuning BCs|
|Jun 2012||Deep extension of Gulf Stream FM; Improved data processing (extending shallow profiles to the surface; improved deep WOA climatology; corrected SST)||May 2012||100 vertical levels; Additional synoptic data (WODB, GTSPP); Gulf Stream, Shelfbreak Front and Recirculation FMs; Improved Data Assimilation; Improved model parameters|
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Additional IODA links
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The goal is multi-resolution data-assimilative modeling to study truly multiscale coastal ocean dynamics and their acoustic effects, with an emphasis on resolving internal tides and long nonlinear internal waves and their interactions with the real ocean, including:
- All coastline, shelf, shelfbreak and deep ocean features; high-resolution steep bathymetry; and, atmospheric fluxes as external forcing.
- Stochastic parameterizations of sub-grid scales (nonlinear internal waves and other effects) for 4D hydrostatics models, and new non-hydrostatic HDG scheme in idealized conditions.
Studies also involve coupling of ocean-acoustic models in 4D, using a hierarchy of acoustic codes, in collaboration with MIT PIs and other PIs. The specific research tasks include:
- Completion of multiscale ocean re-analyses, improving initial conditions and model parameters and increasing resolutions, and
distribution of these fields for collaborative internal wave and acoustic studies with other PIs.
- The MSEAS group has completed a total re-analysis of the atmospheric forcing for the August-September 2006 time period. The real-time WRF and
NOGAPS fields have been compared and evaluated, along with archived COAMPS and NOGAPS fields, in order to determine the most appropriate combination
of available products. Those products have then been compiled/combined/merged into our best estimates of the atmospheric forcing.
The MSEAS group has also completed a reanalysis of the nested ocean simulations of the SW06 experiment (covering the period 14 August to 26 September 2006). The first stage of the reanalysis tested the vertical resolution with increased number of model levels (70 and 100) and variations in their distribution. New algorithms and software for the ocean primitive-equation solver are being used. The second stage reviewed initialization and assimilation procedures, atmospheric and tidal forcing and topography.
- The MSEAS group has completed a total re-analysis of the atmospheric forcing for the August-September 2006 time period. The real-time WRF and NOGAPS fields have been compared and evaluated, along with archived COAMPS and NOGAPS fields, in order to determine the most appropriate combination of available products. Those products have then been compiled/combined/merged into our best estimates of the atmospheric forcing.
- Quantification of multiscale ocean dynamics using term balances and multiscale energy and vorticity analyses focusing on internal tides and waves at the shelf-edge.
- Coupling of oceanic and acoustic deterministic models in 4D for unified studies of idealized and realistic processes, in collaboration with NM, DY and WHOI.
- Development of stochastic parameterizations of sub-grid scale physics based on the statics of our deterministic simulations, and quantify ocean and acoustic uncertainties using our new dynamically orthogonal equations, in collaboration with WHOI and MIT.
- The MSEAS group has developed a solver for a generic system of stochastic differential equations of medium dimension and with external random noise and uncertain initial and boundary conditions. The equations solved are a version of the DO equations. A set of dynamical systems relevant to the IODA project and above goal have been studied.
- Utilization of a new 4D non-hydrostatic HDG model for high-resolution studies of effects on internal waves from the atmosphere, stratification and shelfbreak front features.
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