Wave Exposure Model (WEMo)


Wave Exposure Model (WEMo)

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The Issue

photoHydrodynamic factors profoundly impact the environment of coastal areas. Wind waves, particularly waves associated with storms, are unpredictable and can pose dangerous situations under which to collect scientifically empirical, comparative information. Unfortunately, there are few simple–to–use, inexpensive tools that can provide a quantitative value of wave energy for locations not in the open ocean. Such a tool is needed by resource managers who need to estimate wave energy in coastal regions or in inland waters to gauge susceptibility of developed areas. This tool is also needed by scientists who desire a quantitative measure of wave effects to relate to ecosystem function.


CCFHR scientists have developed an easy-to-use numerical wave exposure model (WEMo) that uses linear wave theory to calculate actual wave height and derived wave energy while taking into consideration wind generation and local water depth characteristics such as shoaling and dissipation from breaking waves. WEMo also provides predictions of seafloor sediment movement.


The model works in a simple Geographic Information System (GIS) format in association with ArcGIS:

  • Forecasts (and hindcasts) quantitative and geographically accurate wave energy and seafloor sediment movement for enclosed or semi-enclosed water bodies (e.g., estuaries and lakes)
  • Foundation for studying or modeling restoration success, seafloor and shoreline erosion, and limits to habitat tolerances.
  • Integrates easily with standard data formats for association with dependent factors such as shoreline erosion, landscape patterns and faunal associations.
  • Guides sample stratification by wave energy regime.
  • Adaptable for use by non-specialists in hydrodynamics; designed for those with basic knowledge of Geographic Information Systems (advanced college class, introductory graduate level classes)
  • Tunable to either chronic or extreme wind events as well as in synchrony with storm surge.


WEMo is being applied to a number of geographic areas including Tampa Bay, FL, Chesapeake Bay, MD & VA, Core Sound and New River, NC, and Prince William Sound, AK.

Examples of potential applications include:

  • seagrass exclusion areas (i.e., areas where wave energy is too high for persistent seagrass habitat);
  • the potential for restoration of seagrass;
  • submersed and shoreline habitat landscape pattern;
  • shoreline susceptibility to hurricanes and other extreme wind events;
  • effect of shoreline structures on habitat.

Downloads - New Version


Wave Exposure Model (WEMo), version 4.0 (New Version)

Version 4.0 (updated March 2010): Available on the WEMo downloads and requirements page and compatible with ArcGIS 9.3
Learn more.


Wave Exposure Model (WEMo) Manual, version 4.0

Version 4.0, March 2010: A new 'Sediment Motion' module is added in this version (WEMo 4.0) to calculate orbital velocities, bottom shear stress and sediment motion for the user-specified particle size
Download the manual (PDF).

Downloads - Previous Versions


Wave Exposure Model (WEMo), version 3.1

Version 3.1, updated September 2008: Available on the WEMo downloads and requirements page and compatible with ArcGIS 9.2
Learn more.


Wave Exposure Model (WEMo) Manual, version 3.1

Version 3.1, updated September 2008 : WEMo was modified in this version (WEMo 3.1) to calculate wave period and maximum wave direction along with automatic wind data processing.
Download the manual (PDF).


Wave Exposure Model (WEMo), version 3.0

Version 3.0 (updated October 2007): Available on the WEMo downloads and requirements page and compatible with ArcGIS 9.1
Learn more.


Wave Exposure Model (WEMo) Manual, version 3.0

Version 3.0, October 2007: WEMo was modified in this version (WEMo 3.0) to calculate wave height and derived Representative Wave Energy along with the relative index (REI) calculated in older WEMo versions.
Download the manual (PDF).


Citation for this work: Tech Memo: NOS NCCOS 65, WEMo (Wave Exposure Model): Formulation, Procedures and Validation

This report describes the working of National Centers for Coastal Ocean Service’s WEMo, capable of predicting the exposure of a site in estuarine and closed water to local wind–generated waves and validation of the model using wave sensors collected data.
Download (PDF).