Lake Jersey Refinement Example AB

Lake Jersey Nesting Refinement Example

Example Menu
1. Introduction
2. Lake Jersey AB
4. Lake Jersey AC
3. Lake Jersey AD
5. Lake Jersey ABD
7. Lake Jersey ADE
6. Lake Jersey ABDC
8. Lake Jersey ACDE

Description

The Lake Jersey test case is primarily used to evaluate the nesting algorithms for the Refinement Grids Super-Class. It is activated with C-preprocessing options LAKE_JERSEY and NESTING. The nesting algorithms in ROMS are two-way by default. The option ONE_WAY can be used for just one-way exchange between donor (dg) and receiver (rg) grids. However, the one-way exchange has no effect whatsoever on the coarser donor grid because there is no feed back of information. Notice that due to its higher spatial and temporal resolutions, the finer grid is better resolving the physical phenomena at smaller scales.

This example is a simple refinement application with two grids: coarse (A) and fine (B). There are two nesting layers because two different time-step sizes are required in ocean_lake_jersey_nested_2g_ab.in:

Number of nested grids.
Ngrids = 2

Number of grid nesting layers. This parameter is used to allow refinement and composite grid combinations.
NestLayers = 2

Number of grids in each nesting layer, [1:NestLayers] values are expected.
GridsInLayer = 1 1

Time-stepping parameters.
NTIMES == 1440 4320 ! Number of time steps
DT == 120.0d0 40.0d0 ! Time-step size (seconds)
NDTFAST == 30 30 ! Number of barotropic steps

Results

The plots below show the results after 2 days of simulation for one-way and two-way nesting configurations. They are plotted with Matlab using the script plot_nesting.m. The refined solution (grid b) is overlayed on top of the coarse grid (a). The color map is rendered using shading flat, meaning there is no interpolation between pixels in the color maps. Click the figure to see a more detailed image. On the resulting page a link to the full resolution image is provided.