Ocean mask ____

Spatial Allocator
1

Dear all,
I need to produce ocean mask file for running CMAQ-WRF two-way. But I am very new with CMAQ. May I ask you please advice me by details how can I produce ocean mask ?
Many thanks in advance,
Best regards,

2

Please take a look at this tutorial on the CMAQ GitHub repo:

If your domain is outside the US and you want to be able to run CMAQ with ocean chemistry, you will need to a shapefile that is appropriate for your domain, but the approach should still be the same.

3

Dear Foley,
Many thanks for your help.I wonder if this is all the process I need to have an ocean file?
Because it was very short and quick.
Best wishes,

4

Greetings,
Were you able to run the script and create the file? That should be all that you need to do. In your run script you will then set the environment variable OCEAN_1 to the location of this file.

If you would like to see an example ocean file, there is one included in these 2016 CMAQ inputs for a domain over the contiguous US with 12km x 12km horizontal grid:
https://drive.google.com/drive/folders/1QyT1I4wgtvYufCKCtE6skfOSK_4KS9Vu

Look under the folder ‘surface’ at the file called ‘12US1_surf.ncf’.

5

Dear Foley,
I did not run it yet,but I read the run script you sent. And it is very short compare to the CMAQ and SMOKE. That is why I wondered!
Dose spatial allocator has only Shapefiles Run Script?

However regarding the run script, may I ask you please advice me about below setting :
setenv INPUT_FILE_MAP_PRJN "+proj=lcc,+lat_1=33,+lat_2=45,+lat_0=40,+lon_0=-97"

setenv INPUT_FILE_ELLIPSOID "+a=6370000.0,+b=6370000.0"

```what are the differences between lat_1 and lat_0? 
and what are +a and +b?
Many thanks,
Best wishes,
6

These environment variables are used to define the map projection based on the PROJ coordinate transformation software.

Here is a brief section on the map projections supported by CMAQ:

Here is the PROJ documentation on the parameters for the Lambert Conformal Conic projection (LCC) that is used in the run script you are looking at.
https://proj.org/operations/projections/lcc.html