Using 2017 NEI platform for a custom grid

SMOKE
1

Hello,

My name is Hamid, and I am a novice in the field of emission processing. I am currently working on preparing CMAQ-ready emission files for my custom domain, which covers the lower British Columbia province in Canada and parts of Washington state in the Pacific Northwest.
I noticed that my domain is covered in the CONUS domain, and I am wondering if I can use the 2017 NEI platform scripts available at https://gaftp.epa.gov/Air/emismod/2017/ to generate the model-ready files for my specific domain.

I need to generate gridded emissions at both 4km and 1 km resolutions for this custom domain. Can I use 4km surrogates that come with the 2017 NEI platform for my coarser grid and only generate the new sets for the 1km domain?

Any help would be appreciated.

regards,
Hamid

2

What is the grid-alignment of your 4KM grid relative to the CONUS 4KM? (same map projection and projection parameters, cell-size, and cell-alignment (are both (XORIG_yours - XORIG_conus )/XCELL and (YORIG_yours - YORIG_conus )/YCELL integers?)

You can use the CONUS surrogates only if the grids are aligned.

2 Likes
3

Agree with Carlie. The map projection is listed in the TSD for 2017 platform (EPA has used the same one for many years):

https://www.epa.gov/air-emissions-modeling/2017-emissions-modeling-platform

The map projection needs to be the same and the grid cells need to be aligned for you to use the provided 4km surrogates.

If that is the case, SMOKE will automatically jump to the right cell to pick up the surrogate data needed for your 4km grid.

You’ll want to properly nest your 1km grid so that it overlays the 4km grid.

1 Like