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applicability in central Africa

Started by mlee, April 29, 2010, 01:00:35 AM

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Hi, I work in Gabon, central Africa and just exploring if SLAMM is possible or appropriate to use. If anyone can point me to examples of SLAMM from equatorial places without much data, or opinions on its applicability, I would very much appreciate it. Thank you, Michelle

Jonathan S. Clough

I have no experience using the model in Africa.  My non-contiguous United States experience consists of a few applications in the Caribbean and Alaska.  There's someone working towards an Australia application.

When you have no decent elevation data you are really relying on a very good conceptual model.  If you are applying the model in a new geographical domain your conceptual model becomes more uncertain.

High vertical-resolution elevation data is probably the most important SLAMM data requirement.  Elevation data demarcates where salt water is predicted to penetrate and, when combined with tidal data, the frequency of inundation for wetlands and marshes.  Elevation data also helps determine the lower elevation range for beaches, wetlands, and tidal flats­the elevation at which point they are inundated too frequently and are predicted to convert to a different type of land-cover or open water.

SLAMM was designed prior to the advent of LiDAR data, so it can certainly model areas with lower quality elevation data.  The way that the model does this is by estimating elevation ranges as a function of tide ranges and known relationships between wetland types and tide ranges.  However, this tool assumes that wetland elevations are uniformly distributed over their feasible vertical elevation ranges or "tidal frames"­an assumption that may not reflect reality.  If wetlands elevations are actually clustered high in the tidal frame they would be less vulnerable to SLR.  If wetland elevations are towards the bottom, they would be more vulnerable.  LiDAR data for any site assists in reducing model uncertainty by characterizing where these marshes exist in their expected range.  Additionally high vertical-resolution data can be used to validate model assumptions regarding the elevation range to tide range relationship for these wetland types.

The mangrove functionality in the model is very simple and mangroves tend to dominate in tropical settings (assuming your setting is tropical?)