In-line sea-salt emission increase for the specified grid in the twoway model.

Hi all, I’m running the twoway model of wrf-cmaq5.0.2. I have a 172172 domain and most of this domain is ocean. Now I want the rate of sea salt emission to increase for some of the grids inside this domain. For example, the rate of sea salt emission is increased for a 2020 grid in the middle. How do I do this?
I am currently trying to modify the SSEMIS.F code. But I checked the code for sea salt emission, where the grids for emission rate are represented by MY_NROWS and MY_NCOLS. These two are assigned by the cluster based on my NPROCS number. I used cluster parallel computing and set nodes=6:ppn=24, which is NPROCS = 144. The MY_NROWS and MY_NCOLS assigned to each of my regions in the actual computation = 15.
The cmaq breaks my entire region into multiple small regions for parallel computation, which leads me to modify only in these 15*15 grids, which then keep getting called over and over again.
I would like to know if there is any index or location information associated with the sea salt emission when it is called, so that the GET_SSEMIS subroutine in SSEMIS.F, the program for sea salt emission, knows where in the larger region this is located? If the current area is at my specified location, the discharge rate increases.
Or is there any other way to do this,? I noticed there are DESID modules that seem to control emissions, but I’m not sure if they are available in cmaq5.0.2.
Thanks for all the help.