Depth-Attenuated Wave Exposure Indices for Pacific Canada

Pacific Canada's marine regions feature five raster layers of depth-attenuated Relative Wave Exposure Index (REI) values, normalized from 0 (protected) to 1 (exposed). The data provides wave exposure estimates at bottom depth for species distribution modeling, with coverage extending to 50 meters depth and up to 5 kilometers from shore. It was produced by Fisheries and Oceans Canada using effective fetch and modeled wind data.

Use Cases

• Incorporate REI values as an environmental predictor in species distribution models for nearshore marine habitats.
• Analyze the correlation between depth-attenuated wave exposure and species presence data within specific marine regions like Nearshore_HG or Shelf_SalishSea.
• Use the raster layers to map relative exposure gradients from protected to exposed areas for coastal zone management planning.
• Validate or compare modeled REI values against in-situ wave data at the specified grid cell locations derived from the gridded nearshore fetch source.

Strengths

• Provides five distinct raster layers covering major marine regions of Pacific Canada.
• Index values are depth-attenuated, offering more relevant exposure estimates for shallow, nearshore benthic environments.
• Data is normalized between 0 and 1, allowing for consistent comparison across different geographic regions.

Limitations

• Spatial coverage is limited to areas within 5 km of shore and depths shallower than 50 meters.
• The REI is a relative index derived from models (fetch and wind), not a direct measurement of wave energy.
• The underlying source data (gridded nearshore fetch) may inherit its own spatial resolution and accuracy constraints.

Provenance

Source

Fisheries and Oceans Canada

Collection Method

Calculated from effective fetch (derived from gridded nearshore fetch data) combined with modeled wind data, following the Bekkby et al. 2008 methodology.

Freshness

Last updated March 24, 2026.

Geography

Marine regions of Pacific Canada, specifically Nearshore_HG, Nearshore_NCC, Nearshore_QCS, and Shelf_SalishSea.