Search found 11 matches

by soilinkin
Mon Apr 17, 2023 4:33 am
Forum: ROMS Discussion
Topic: Different result after cutting off land cells
Replies: 0
Views: 4647

Different result after cutting off land cells

Hi, I have my model almost set up. But in order to save some run time , I have decided to change the geometry of one river so I have less cells on ETA direction. After converting the grid and all the necessary inputs for the dimension change, I realized that the model results are slightly changed ...
by soilinkin
Mon Dec 20, 2021 6:27 pm
Forum: ROMS Discussion
Topic: Variables for Masked Grid Cells
Replies: 5
Views: 9573

Re: Variables for Masked Grid Cells

Here for example is what NOAA NOS did to pad out cells in the land for their Chesapeake Bay CBOFS grid, which was computed with Delft tools. This shows "dy" grid spacing (1/pn) plotted in the grid i,j coordinates, because the filled bogus lon/lats in the land mess up my plotting routines (if lon ...
by soilinkin
Mon Dec 20, 2021 2:12 pm
Forum: ROMS Discussion
Topic: Variables for Masked Grid Cells
Replies: 5
Views: 9573

Re: Variables for Masked Grid Cells

Yes, that's a problem. ROMS computes on all cells and then applies the masks. So, NaN values just inside the coastline can propagate into the interior. Zero values of, say, depth (but also other grid metrics) can cause divide-by-zero. Just fill the land with modest finite values and the masks ...
by soilinkin
Mon Dec 20, 2021 5:07 am
Forum: ROMS Discussion
Topic: Variables for Masked Grid Cells
Replies: 5
Views: 9573

Variables for Masked Grid Cells

Hi, I have a model run blow-up at the first time step. My first suspect is the grid file generated with Delft3D. Variables like coordinates are all set to -999 or Nan for the masked grid cells when the grid is generated in Delft3D, while all the unmasked cells have normal values. So there is no way ...
by soilinkin
Wed Aug 25, 2021 5:43 pm
Forum: ROMS Discussion
Topic: Thin Wall Between Grid Cells
Replies: 3
Views: 5524

Re: Thin Wall Between Grid Cells

Typically to provide a permanent wall, then use the mask _u _v _rho variables. ROMS is solved on a staggered grid, so when you set the mask_rho, then edit_mask (or similar) can determine the appropriate settings for mask_u and mask_v and mask_psi. However, it seems you want a special case, where 2 ...
by soilinkin
Wed Aug 25, 2021 4:25 pm
Forum: ROMS Discussion
Topic: Thin Wall Between Grid Cells
Replies: 3
Views: 5524

Thin Wall Between Grid Cells

Hi, all. I have a question hoping someone can help. Is it possible to put a thin wall between 2 grid cells, so there is no exchange at all between the cells? I have a situation that there is a thin wall in my domain, to separate neighboring cells, but I can't find any information related. I imagine ...
by soilinkin
Fri Aug 13, 2021 6:57 pm
Forum: ROMS Discussion
Topic: Multiple Wind Field
Replies: 3
Views: 9057

Re: Multiple Wind Field

You can merge them before having ROMS read them and regrid/rotate them if they are both on lat/lon grids of the same resolution. You can copy the ROMS code for reading then regrid/rotating winds to also read/rotate/regrid say Unwind2 and Vwind2. Then you can come up with some means of merging them ...
by soilinkin
Thu Aug 12, 2021 6:46 pm
Forum: ROMS Discussion
Topic: Multiple Wind Field
Replies: 3
Views: 9057

Multiple Wind Field

Hi all I have a model domain that will require 2 different wind fields to be applied to different parts of the domain. I understand that if I have a global wind field in the forcing file, the global wind will be interpolated and rotated to fit the whole domain; and if I have a fully gridded wind ...
by soilinkin
Fri May 28, 2021 6:45 pm
Forum: ROMS Discussion
Topic: Boundary Condition Choice
Replies: 4
Views: 10422

Re: Boundary Condition Choice

kate wrote: Thu May 27, 2021 5:17 pm
Adding a strip of land-masked cells is fair amount of work.
This is why it is good to know your tools. We have landmask editing in both Matlab and Python. Also, it is worthwhile to learn to edit netcdf files in SOME programming language.
Thank you.
by soilinkin
Thu May 27, 2021 2:07 pm
Forum: ROMS Discussion
Topic: Boundary Condition Choice
Replies: 4
Views: 10422

Re: Boundary Condition Choice

If you put a one-cell wide strip of masked land down most of your west boundary, the open boundary condition can apply just to the "estuary". Thanks for your help. I thought about this as a possibility, but I wonder whether there is other option. This is because the pic I attached is a simplified ...
by soilinkin
Wed May 26, 2021 8:32 pm
Forum: ROMS Discussion
Topic: Boundary Condition Choice
Replies: 4
Views: 10422

Boundary Condition Choice

Hi, I am new here trying to learn ROMS. I have a question regarding the selection of boundary condition, hand hope someone can help. I have a simplified domain like in the attached pic. I have ocean at east and south which can use open boundary. I have coastline and some river with inflows at the ...