Hi-Resolution Wave Height Data from inVEST Coastal Vulnerability

Hello,

Is there an expanded sample data set for the Wave Energy InVEST module? I’m working as part of a project using a model incorporating wave height data as a parameter. A member of this project used Natural Capital data in the past to obtain this. What I’m looking for is a point grid similar in appearance to the NAmerica_EastCoast_4m where each point has an associated lat-long coordinate, significant wave height, and peak wave period.

The problem is that the data I’m finding is on a coarser scale than the data they got from Natural Capital a few years back. Additionally the points are limited to the oceanside and do not include bodies like the Delaware or Chesapeake Bays, areas that are critical to our model.

As far as I understand they got it straight from the Natural Capital data and didn’t have to create a custom data set from Wavewatch III logs. I’m reaching out to see if anyone knows where I can find this higher resolution data set, maybe I’m just looking in the wrong places.

Thanks!

@diehl.theo, the Wave Energy data we ship with the InVEST installer (here’s the Wave Energy data for InVEST 3.9.0) contains a couple of vectors at various grid resolutions and spatial regions. But these datasets haven’t been updated in several years … they might be of the same generation as the existing file you have.

Let us know if these aren’t quite what you’re looking for and we’ll see what we can do!
James

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@jdouglass

Hi, thanks very much for getting back to me on this. Before posting this, I had made sure to spend a bit of time combing through the inVEST Wave Energy sample data in the hopes that I’d find this vector in question, but came up short. I believe I was looking through the same data set you linked, as I initially downloaded 3.9.0. In either case I looked through the data from your link and unfortunately still haven’t found this vector.

If it helps, this is a screenshot of the previous data obtained from Natural Capital, just to get an idea of what I’m looking for.

As you can see the spatial resolution of the grid points is higher and hugs the coastline at a bit finer scale, as compared to the screenshot of the NAmerica_EastCoast_4m grid from the sample data set I linked in my first post. Thanks again for your help.

Hi @diehl.theo, the data in that screenshot looks like it could have been generated by the Coastal Vulnerability model. It plots points along a coastline and interpolates the coarse, offshore WW3 data onto those points. Then it computes wave height & period at those points from the wind velocities in the WW3 data and ocean depths and fetch distances based on user input bathymetry. Those outputs will be in the intermediate/wind_wave folder in wave_energies.gpkg

http://releases.naturalcapitalproject.org/invest-userguide/latest/coastal_vulnerability.html#intermediate-directory

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Hi @dave ,

Thanks for the response, I have a hunch this may be what I’m looking for. Do you have any recommendations on where I can obtain bathymetry data in the same format as the TIF file that’s included with the sample data set? Can I use the global_dem.tif file that’s included in the Base_Data folder? If so, can this also be used for the DEM input for step 8? Sorry for the question dump, thanks again to all for your help.

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@diehl.theo no problem. GEBCO is a tried & true source of bathymetry data. GEBCO Gridded Bathymetry Data

That’s probably what the sample data was based on, but it’s many years old so might be worth getting their latest offering. The estimated wave heights are based on the average water depth along the fetch ray. So there’s not a ton of incentive to use an extremely high-resolution batymetry – the values get averaged out.

Yes, you may use the same global_dem.tif for the DEM input. It’s not a factor in the wave height math, so if that’s all you care about then there’s no reason to look for a higher resolution data source for the DEM.

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Hi Dave, thanks again for your help. Is there a place in the Coastal Vulnerability intermediate output folder that I can find the values that are used to assign the 1-5 rankings for wind, wave, relief, and SLR in the final output? Specifically I’m looking for the raw wave energy measurement in kW/meter that is used to assign the final wave exposure rank for each shore point. Thanks.

Hi @diehl.theo, you may have figured this out by now, but the data that is binned by percentiles to create the 1-5 rankings will be in intermediate/intermediate_exposure.gpkg. For the wave variable, those are the kW/m values. If you want to trace things back even further, then the data used to compute those intermediate values will be in other subfolders like intermediate/wind_wave/. These variables are detailed in this section of the User’s Guide here: Coastal Vulnerability Model — InVEST documentation

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That’s the one! I somehow managed to pass over that file in my scouring. Thanks once again Dave.

One more question for you - does the presence of Habitat Type and Geomorphology data have an effect on the calculation of the wave energy at a given shore point? I’m using the CV model with the intention of extracting the wave energy output data along an area of coastline. I’m on a short deadline so if I can bypass the extra steps associated with gathering habitat type and geomorphology data that would be preferable, if the wave energy data is indeed calculated independent of those variables. Thanks again!

No it does not. Those intermediate wave energy values are described in the equations in this section of UG Coastal Vulnerability Model — InVEST documentation

Caveat: the CV model does not do any hydrodynamic modeling of wave & wind processes. It applies general equations to compute wave energy based on average wind & wave conditions given by the WW3 model, and based on fetch distances. It’s main purpose is to quantify relative amounts of wave exposure across the coastline based on this readily available data, not necessarily to produce the most accurate measure of wave power at any given point.

The “Limitations” section of the User’s Guide is worth reading on this topic as well.

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