Mid- to Inner-Shelf Coupled ROMS–SWAN Model–Data Comparison of Currents and Temperature: Diurnal and Semidiurnal Variability

2016 ◽  
Vol 46 (3) ◽  
pp. 841-862 ◽  
Author(s):  
Nirnimesh Kumar ◽  
Falk Feddersen ◽  
Sutara Suanda ◽  
Yusuke Uchiyama ◽  
James McWilliams
Keyword(s):  
Heat Budget ◽  
Time Derivative ◽  
Phase Speed ◽  
Internal Tide ◽  
Internal Variability ◽  
Flux Divergence ◽  
Inner Shelf ◽  
Swan Model ◽  
San Pedro ◽  
San Pedro Bay

AbstractAccurately representing diurnal and semidiurnal internal variability is necessary to investigate inner-shelf to midshelf exchange processes. Here, a coupled Regional Ocean Model System (ROMS)–Simulating Waves Nearshore (SWAN) model is compared to observed diurnal and semidiurnal internal tidal variability on the mid and inner shelf (26–8 m water depth) near San Pedro Bay, California. Modeled mean stratification is about one-half of that observed. Modeled and observed baroclinic velocity rotary spectra are similar in the diurnal and semidiurnal band. Modeled and observed temperature spectra have similar diurnal and semidiurnal band structure, although the modeled is weaker. The observed and modeled diurnal and semidiurnal baroclinic velocity- and temperature-dominant vertical structures are similar and consistent with mode-one internal motions. Both observed and modeled diurnal baroclinic kinetic energy are strongly correlated to diurnal wind forcing and enhanced by subtidal vorticity-induced reduction in the inertial frequency. The mid- and inner-shelf modeled diurnal depth-integrated heat budget is a balance between advective heat flux divergence and temperature time derivative. Temperature–velocity phase indicates progressive semidiurnal internal tide on the midshelf and largely standing internal tide on the inner shelf in both observed and modeled. The ratio of observed to modeled inferred phase speed is consistent with the observed to modeled stratification. The San Pedro Bay modeled semidiurnal internal tide has significant spatial variability, variable incident wave angles, and multiple local generation sites. Overall, the coupled ROMS–SWAN model represents well the complex diurnal and semidiurnal internal variability from the mid to the inner shelf.

scholarly journals Midshelf to Surfzone Coupled ROMS–SWAN Model Data Comparison of Waves, Currents, and Temperature: Diagnosis of Subtidal Forcings and Response

2015 ◽  
Vol 45 (6) ◽  
pp. 1464-1490 ◽  
Author(s):  
Nirnimesh Kumar ◽  
Falk Feddersen ◽  
Yusuke Uchiyama ◽  
James McWilliams ◽  
William O’Reilly
Keyword(s):  
Heat Flux ◽  
Vertical Mixing ◽  
Circulation Model ◽  
Ocean Model ◽  
Vertical Shear ◽  
Flux Divergence ◽  
Inner Shelf ◽  
Swan Model ◽  
Temperature Spectra ◽  
Shelf Region

AbstractA coupled wave and circulation model that includes tide, wind, buoyancy, and wave processes is necessary to investigate tracer exchange in the shelf region. Here, a coupled Regional Ocean Model System (ROMS)–Simulating Waves Nearshore (SWAN) model, resolving midshelf to the surfzone region of the San Pedro Bay, California, is compared to observations from the 2006 Huntington Beach experiment. Waves are well modeled, and surfzone cross- and alongshore velocities are reasonably well modeled. Modeled and observed rotary velocity spectra compare well in subtidal and tidal bands, and temperature spectra compare well in the subtidal band. Observed and modeled mid- and inner-shelf subtidal velocity ellipses and temperature variability determined from the first vertical complex EOF (cEOF) mode have similar vertical structure. Although the modeled subtidal velocity vertical shear and stratification are weaker than observed, the ratio of stratification to shear is similar, suggesting model vertical mixing is consistent with observations. On fortnightly and longer time scales, the surface heat flux and advective heat flux divergence largely balance on the inner shelf and surfzone. The surfzone and inner-shelf alongshore currents separated by 220 m are unrelated. Both modeled and observed subtidal alongshelf current and temperature are cross-shelf coherent seaward of the surfzone. Wind forcing explains 50% of the observed and modeled inner-shelf alongshore current variability. The observed and modeled inner-shelf alongshelf nonuniformities in depth-averaged alongshore velocities are similar. Inferred, inner-shelf, wave-induced, cross-shore exchange is more important than on the U.S. East Coast. Overall, the coupled ROMS–SWAN model represents well the waves and subtidal circulation dynamics from the midshelf to the surfzone.

San Pedro Bay Ports Rail Enhancement Program: 2010 Update

2011 ◽  
Author(s):  
Michael Leue ◽  
Carlo Luzzi
Keyword(s):  
Los Angeles ◽  
Program Implementation ◽  
Development Process ◽  
System Development ◽  
Implementation Process ◽  
Current Status ◽  
Infrastructure Development ◽  
San Pedro ◽  
Rail System ◽  
San Pedro Bay

The San Pedro Bay Ports of Long Beach and Los Angeles continue to provide vital rail connections to the rest of the country. The Rail Enhancement Program sets forth the rail improvements necessary to maintain performance as cargo volumes grow through the year 2035. Implementation of the Rail Enhancement Program has faced hurdles including environmental permitting, funding and competing stakeholder concerns. Cargo growth eased in the years approaching 2010, but the timing of proposed improvements to the rail infrastructure remains critical and challenging. The Rail Enhancement Program is the result of work over the past ten years. Conditions affecting the program have continued to change since the original Rail Master Planning Study of 2000. Updates to the Master Plan have been performed in 2005 and 2010. These documents provide analyses and recommendations for rail improvements to maintain adequate rail service on the Alameda Corridor and through the Port to its rail yards. In developing the Rail Enhancement Program, simulation is used to understand the impacts of increasing cargo volumes on the rail system and to investigate infrastructure and operating improvements required to address deficiencies and to determine improvements to efficiently handle projected traffic. This paper describes the development process with a summary of the analysis methods, resulting proposed rail projects, implementation process and current status of implementation. The steps of the rail system development process include the following: • Evaluation of existing and proposed rail operations; • Conceptual design of over forty potential rail improvement projects; • Analysis of the capacity of existing and proposed facilities; • Scheduling of project development to meet demand; • Estimation of environmental, community and regional impacts and benefits; • Determination of schedule including environmental permit requirements; • Development of project funding plans; and • Preparation of engineering designs and construction documents. The paper will conclude with a summary of the status of key projects from the Rail Enhancement Program. Implementation of the Rail Enhancement Program has included permitting, funding and design efforts on individual projects. The projects currently under development total $1B out of the overall $2B program. The Rail Enhancement Program provides significant benefits to operating efficiencies, environmental impacts and economic impacts. Implementation has been a challenging effort and illustrates the myriad obstacles facing public infrastructure development.

scholarly journals Energy transformations and dissipation of nonlinear internal waves over New Jersey's continental shelf

2010 ◽  
Vol 17 (4) ◽  
pp. 345-360 ◽  
Author(s):  
E. L. Shroyer ◽  
J. N. Moum ◽  
J. D. Nash
Keyword(s):  
Continental Shelf ◽  
Internal Waves ◽  
Turbulent Mixing ◽  
Internal Tide ◽  
Flux Divergence ◽  
Wave Interactions ◽  
Nonlinear Internal Waves ◽  
Dissipative Loss ◽  
Peak Energy

Abstract. The energetics of large amplitude, high-frequency nonlinear internal waves (NLIWs) observed over the New Jersey continental shelf are summarized from ship and mooring data acquired in August 2006. NLIW energy was typically on the order of 105 Jm−1, and the wave dissipative loss was near 50 W m−1. However, wave energies (dissipations) were ~10 (~2) times greater than these values during a particular week-long period. In general, the leading waves in a packet grew in energy across the outer shelf, reached peak values near 40 km inshore of the shelf break, and then lost energy to turbulent mixing. Wave growth was attributed to the bore-like nature of the internal tide, as wave groups that exhibited larger long-term (lasting for a few hours) displacements of the pycnocline offshore typically had greater energy inshore. For ship-observed NLIWs, the average dissipative loss over the region of decay scaled with the peak energy in waves; extending this scaling to mooring data produces estimates of NLIW dissipative loss consistent with those made using the flux divergence of wave energy. The decay time scale of the NLIWs was approximately 12 h corresponding to a length scale of 35 km (O(100) wavelengths). Imposed on these larger scale energetic trends, were short, rapid exchanges associated with wave interactions and shoaling on a localized topographic rise. Both of these events resulted in the onset of shear instabilities and large energy loss to turbulent mixing.

scholarly journals STUDY ON THE MECHANISM OF INUNDATION CHARACTERISTICS AROUND THE SAN PEDRO BAY INDUCED BY TYPHOON HAIYAN

2015 ◽  
Vol 71 (2) ◽  
pp. I_1675-I_1680
Author(s):  
Yusuke TAGUCHI ◽  
Yoshimitsu TAJIMA ◽  
Shunichiro NAKAMURA ◽  
Yusuke YAMANAKA
Keyword(s):  
San Pedro ◽  
San Pedro Bay

scholarly journals Systematic Bias in Baroclinic Energy Estimates in Shelf Seas

2016 ◽  
Vol 46 (9) ◽  
pp. 2851-2862 ◽  
Author(s):  
Gordon R. Stephenson ◽  
J. A. Mattias Green ◽  
Mark E. Inall
Keyword(s):  
Phase Speed ◽  
Internal Tide ◽  
Energy Estimates ◽  
Systematic Bias ◽  
Energy Fluxes ◽  
Sources And Sinks ◽  
Barotropic Flow ◽  
Shelf Seas ◽  
Low Pass ◽  
Low Pass Filters

AbstractA simple model of an internal wave advected by an oscillating barotropic flow suggests flaws in standard approaches to estimating properties of the internal tide. When the M2 barotropic tidal current amplitude is of similar size to the phase speed of the M2 baroclinic tide, spectral and harmonic analysis techniques lead to erroneous estimates of the amplitude, phase, and energy in the M2 internal tide. In general, harmonic fits and bandpass or low-pass filters that attempt to isolate the lowest M2 harmonic significantly underestimate the strength of M2 baroclinic energy fluxes in shelf seas. Baroclinic energy flux estimates may show artificial spatial variability, giving the illusion of sources and sinks of energy where none are actually present. Analysis of previously published estimates of baroclinic energy fluxes in the Celtic Sea suggests this mechanism may lead to values being 25%–60% too low.

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