Model help:Waves

Waves

WAVES controls the wave climate input to the CEM longshore transport module (CEM).

Introduction

WAVES is an essential part of the original CEM model (Ashton et al., 2006) that has been componentized to consist of two separate components; the longshore transport component CEM and the wave component WAVES. The original model was designed to investigate an instability in the shape of a coastline caused by waves approaching with ‘high’ angles (with the angle between deepwater crests and the coast > 45 degrees).

WAVES describes a simplified directional wave climate by two main input parameters: the asymmetry of the incoming waves angle and the proportion of high-angle waves. This model is not designed to accurately simulate a specific geographic location in detail but rather to more generally represent how a shoreline with highly mobile sediment may respond to varying wave angles. The value in this model is in the breadth it offers in representing how different wave climates can result in different potentially interesting shoreline configurations.

Model input parameters

Input files and Directories
You can use these settings to change the names of the output files generated by the WAVES component.One can set the ‘site prefix’ and the ‘case prefix’ to identify unique wave settings experiments. These prefixes are used throughout the CMT and allow users to organize their simulations according to geographic setting (site prefix) and simulation scenario (case prefix). The fields do need to be filled in, in this project these two fields determine the name of the wave output files.

Run parameters
All wave parameters are the far-field, incoming wave characteristics, assumed to be deep-water values.

H	incoming wave height	m
P	incoming wave period	s
A	asymmetry of the incoming wave field	[0-1]
U	proportion of high angle, unstable waves	[0-1]

The variable A controls the directional distribution of waves, representing the fraction of waves approaching from the left or right, from the perspective of a person looking out to sea. It is designated to be a value between 0 and 1. A designation of greater than 0.5 indicates that the majority of wave energy is approaching from the left where a designation of 1.0 indicates all wave energy approaches from the left. A designation of 0.5 indicates wave energy approach is evenly distributed between the left and right. A designation of less than 0.5 indicates the majority of wave energy is approaching from the right where a designation of 0 indicates all wave energy approaches from the right

The variable U controls the general directional spread of the approaching waves, here split into whether waves approach from angles great than or less than the one which maximized alongshore sediment transport (approximately 45 degrees). High-angle waves approach with angles greater than 45 degrees and low-angle waves approach more directly onshore. (Note that in both cases, the angles of the breaking waves are typically significantly lower.)
U varies between 0-1, controls the fraction of high-angle waves, where a value of less than 0.5 indicates wave energy predominately approaching from a low angle and a designation greater than 0.5 indicates a predominance of high-angle (unstable waves). A value of 0 results in only low-angle waves, evenly distributed between 0 and 45 degrees; a values of 1 would results in only high-angle waves evenly distributed between 45 and 90 degrees. This variable is probably the most important control on the behavior of coupled CEM-WAVES simulations using this simplified wave climate scheme. If CEM is being employed to simulate the self-organization of a coast, values of U larger than 0.5 should be used. For scenarios involving delta evolution, values less than 0.5 tend to be more reasonable (unless a local wave climate has that character). There is no specific method for deriving these terms (U and A) from natural wave climate conditions. Either A and U can be toggled to emulate a natural wave or other methods can be employed (not yet functional) where a natural wave climate can be enetered into the model.

Model output parameters

output variable1	variable description1	variable units1
variable2	description2	units2

Coupling parameters

Uses ports

This will be something that the CSDMS facility will add

Provides ports

This will be something that the CSDMS facility will add

Main equations

A list of the key equations. Notes on the numerical scheme. HTML format is supported; latex format will be supported in the future

Notes

Any notes, comments, you want to share with the user

Examples

An example run with input parameters as well as a figure / movie of the output

Follow the next steps to include images / movies of simulations:

• Upload file: https://csdms.colorado.edu/wiki/Special:Upload
• Create link to the file on your page: [[Image:<file name>]].

See also: Help:Images or Help:Movies

Developer(s)

Andrew Ashton, componentizing of WAVES done by Eric Hutton

References

Ashton A., Murray B.A. Arnault O. Formation of Coastline Features by Large-Scale Instabilities Induced by High-Angle Waves. Nature Magazine. Volume 414. 15 November 2001
Ashton A.D., Murray A.B. High-Angle Wave Instability and Emergent Shoreline Shapes: 1. Wave Climate Analysis and Comparisons to Nature. Journal of Geophysical Research. Volume 111. 15 December 2006.
Ashton A.D., Murray A.B. High-Angle Wave Instability and Emergent Shoreline Shapes: 2. Wave Climate Analysis and Comparisons to Nature. Journal of Geophysical Research. Volume 111. 15 December 2006.

Links

Any link, eg. to the model questionnaire, the e-book that is on the CSDMS web, Gary Parkers website....