Spray Aerosol Emissions from the Great Lakes - Creating surf-zone and lake masks similar to the SSEMIS module


I am working on a project to enable spray aerosol emissions from the Great Lakes in CMAQ v5.3. The current SSEMIS module (sea spray aerosol module) uses an Ocean mask (Grid_Data%OCEAN) and a surf-zone mask (Grid_Data%SZONE) and I would like to create similar masks for the Great Lakes area. Can someone please suggest a way to create fractional lake cover and fractional lake surf-zone cover variables in grid data?

Thank you!


One approach to generate the ocean mask file using the Spatial Allocator is described as Option 1 in this tutorial. While I don’t have first-hand experience using this tool to generate the ocean mask file, the challenge may be that the surfzone shapefile distributed with this tool only considers the open ocean, not the Great Lakes. So while you could use this tool and approach to generate an ocean mask file that includes the Great Lakes, you’d have to provide a shapefile that includes the necessary information.

Once you have an ocean mask file for the Great Lakes, I assume you’d also want to make modifications to the CMAQ sea salt aerosol emissions module given that the salinity of the Great Lakes is much lower than typical ocean values.

Hi Christian,

Thank you so much for your reply! I already checked this Spatial Allocator tool however as you mentioned, the surfzone shapefile distributed with this tool only considers the open ocean. Are there any tutorials on how to generate my own shapefiles (I am not very familiar with this kind of files)?

Yes, I will also implement other modifications to the CMAQ sea spray module to account for different salinity, aerosol size distributions, and speciation.

No, unfortunately I am not aware of any tutorials on how to generate your own shapefile, and I also don’t have any background in GIS that might help here.

It may help to add the “Spatial Allocator” category to your post to get input from users who do have such background.

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Thank you for the suggestion. It is now under “Spatial Allocator” Category.

I am getting a broken link for the tutorial. Is it possible to get an updated link?

My apologies, I mistakenly linked to the tutorial in our private CMAQ development repo. The correct URL is as follows:

I have updated my original post with this link.

You can find this tutorial in the same directory as all the other tutorials in the Users Guide under DOCS/Users_Guide/Tutorials/