Property:Describe numerical limitations
From CSDMS
This is a property of type Text.
G
Does not consider influence of cross-shore sand transport, not intended for short-term storm-induced shoreline change. No wave reflection from structures. No direct provision for changing tide level. +
H
Dpeending on the size of the DEM this can be quite a slow process, particularly the third step. +
W
Dynamics, chemistry, RT, microphysical, and slab ocean model are all coupled, thus the model runs slowly. +
G
Equation set is still and uses robust but relatively inefficient solvers. Recommend testing with coarse grid resolutions (say, 20x20 cells) before attempting larger/finer grids. +
Explicit forward in time finite volume method limits maximum timestep/resolution combination. This can be managed using the adaptive timestep solver that is included. +
W
Explicit schemes make high resolution runs expensive. +
D
Explicit solver can go unstable, and it is not always obvious. Make sure to check resulting soil depths in the landscape to look for instabilities. +
S
Extreme deformation of mesh is expected during large deformationin the updated Lagrangian formulation but prevented by regridding. The numerical diffusion due to regridding, however, can sometime make structures (e.g. shear localization) lose desired sharpness.
Regridding itself fails from time to time. +
B
Free surface formulation does not support rapid changes in water elevation like hydraulic jumps in rivers. +
I
If you will be processing very large landscapes then you may need to configure PETSc with the --with-64-bit-indices option. +
M
Implicit code. Very stable. Very efficient +
T
In general, Matlab stores all data in the main memory. Manageable grid size will depend on your available RAM. For conveniently working with grids with ~5000x5000 rows and columns, a 4Gb of RAM will likely be sufficient. +
C
R
C
Matlab may max out memory if drainage basin is too large. Since this is a simplified landscape with wrap-around boundary conditions, one workaround is to do numerous smaller runs and add the output. +
M
Maximum timestep must be determined by trial. +
S
Model Assumptions
* Mild bottom slope and negligible wave reflection
* Spatially homogeneous offshore wave conditions
* Steady-state waves, currents, and winds
* Linear refraction and shoaling
* Depth-uniform current
* Bottom friction is neglected +
T
Model Limitations
* TOPMODEL only simulates watershed hydrology, although studies have been conducted to modify it to
simulate water quality dynamics.
* TOPMODEL can be applied most accurately to watersheds that do not suffer from excessively long dry
periods and have shallow homogeneous soils and moderate topography.
* Model results are sensitive to grid size, and grid size <=50 m is recommended. +
I
