Labs WMT ROMSLIte WaveForcing

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Introduction to Regional Ocean Modeling - Wave Forcing


This lab has been designed and developed by Courtney Harris, Julia Moriarty, and Danielle Tarpley Virginia Institute of Marine Sciences, Gloucester Point, VA
with assistance of Irina Overeem, CSDMS, University of Colorado, CO

Classroom organization
This lab is the third in a series of introduction to the Regional Ocean Modeling System (ROMS) for inexperienced users. ROMS is a three-dimensional hydrodynamic ocean model. It solves the conservation of mass and 3D momentum equations and includes transport equations for temperature and salinity. Here we present a basic configuration of ROMS in the framework of the Web Modeling Tool (WMT), it is designed for inexperienced modelers to look at a river plume affecting the coastal ocean and sediment transport. Specifically in this lab we will investigate the effects of incoming waves on sediment erosion and transport.
This lab will likely take ~ 3hours to complete in the classroom.
If you have never used the Web Modeling Tool, learn how to use it here. The WMT allows you to set up simulations, but once you are ready to run them, you will need an account on the CSDMS supercomputer to submit your job. More information on getting an account can be found here HPCC Access. Note that getting permission for access takes a few days after your application.

Learning objectives

Skills

  • familiarize with a basic configuration of the Regional Ocean Modeling System
  • hands-on experience with visualizing NetCDF output with Matlab or Panoply.

Technical learning objectives: learn about

  • how to describe waves
  • wave orbital velocities and current affects bed shear stresses
  • the effects of waves on fluvial deposition



Lab Notes

>> Open a new browser window and open the Web Modeling Tool here and select the ROMS project
>> This WMT project is unique in that there is only a single driver, ROMS-Lite. It is a pre-compiled instance of the larger ROMS system specially configured for teaching use.

Select ROMSLite .png ROMS liteDriver.png

The numerical experiment has been designed to use idealized inputs (see Lessons 1 and 2), including temporally constant wave energy. The standard inputs for the WMT ROMS-Lite are a significant wave height of 2 m, a dominant* wave period of 10 s, and a wave direction of 1.6 radians (from North???****). Currents in the model vary in response to the river plume entering the shelf, but are generally directed alongshore in response to a larger-scale current *created by the open boundary conditions*. Together, the modeled waves and currents affect estimates of bed shear stresses, as well as sediment transport and deposition on the shelf.



>> Run the base case configuration. It is purposely configured to be short and fast (it takes only a few minutes to run). Download the zip file with your simulation output from the run status window

Download RunStatusWindow.png

The ocean_riverplume2.nc file contains all of the important model output in a NetCDF file.

Plot the current-induced and wave-induced bed stresses. Do waves or currents dominate the bed stress? Does your answer depend on what part of the shelf you are looking at? Why?
Plot the sediment bed deposit. Over what water depths can the waves and/or currents suspended riverine sediments from the seabed?  How does your answer vary for the different classes of sediment?

References

  • Haidvogel, D. B., H. G. Arango, K. Hedstrom, A. Beckmann, P. Malanotte-Rizzoli, and A. F. Shchepetkin, 2000: Model evaluation experiments in the North Atlantic Basin: Simulations in nonlinear terrain-following coordinates, Dyn. Atmos. Oceans, 32, 239-281.
  • Warner, Sherwood, Signell, Harris, and Arango, 2008 "Development of a three-dimensional, regional, coupled wave, current, and sediment-transport model", Computers & Geosciences.
  • More information on the ROMS Sediment transport model