ocean grid creation

[afrigola@marum_de]

I am trying to create an ocean grid similar to the gx1v3 one, using mk_grid.csh. As far as I know, the parameter values that were used to create the gx1v3 grid are unknown (dyeq, dsig, jcon and coordinates of the grid poles). Are there any tools to visualize the data inside the binary grid file? The main problem I am facing is developing tools to compare my grid with the default one. If I could do that, then I could play with the parameter values in mk_grid.csh until I got a good match with the default grid.I thought of using the default grid gx1v3 instead of a customized one. But I am not sure it fits my experiment. In my topography/bathymetry there is still ocean south of 80 degrees South. In the setup tools guide I read that "the grid poles must be placed 1-2 land cells from the edge of the continent". Does this condition somehow say that at the bottom edge of the grid (for j=0 and j=1) one must have land cells? that one can't have ocean in there?Lg,Amanda

 

[nanr]

Hi Amanda -Here is an example of an NCL script that can read the binary KMT and grid files and write them back out in NetCDF.  You can modify the KMT point by point using the example in this script.  Remember you will need to reproduce the coupler mapping files if you change the land/sea mask. Pole points need to be 1 to 2 grid boxes from the continental edge.  https://www2.cesm.ucar.edu/working_groups/Paleo/docs/paleo-documentation/convert-binary-kmt-netcdfbest regards - nan 

 

[afrigola@marum_de]

Dear Nan,Thanks a lot for the ncl script. Just one more question, I am not sure about the meaning of the sentence "Pole points need to be 1 or 2 grid boxes from the continental edge". Does it imply that both at the top and at the botton of the region mask I must have 1 or 2 rows with land (not ocean)? Your refer to grid boxes in the kmt and region mask binary files, right? Not to grid boxes in the initial topo/bathymetry .nc file. Am I right?
best regards,Amanda

 

[nanr]

Hi Amanda - When I need to choose new ocean grid poles, I identify points from the netCDF lat/lon topography/bathymetry file.  These points must be inland by at least one to two grid cells.  The region mask reflects the pole placement, therefore, you automatically have land at the top/bottom of the region mask as it converges around the poles.  Nan

 

[afrigola@marum_de]

Dear Nan,I did what you said, I chose ocean grid poles inland and at leat 2 grid cells away from the coastline in the topo/bathy file. However, having land at the top of the region mask still depends on the value of jcon that I choose. So for example, for jcon=40  there isnt land everywhere at the top of the region mask, whereas for jcon=55 there is. The problem with using jcon=55 was that I was obtaining negative areas in the corresponding mapping files and the model was crashing. I could send you plots of these two region masks, with jcon=40 and jcon=55 to illustrate what I mean. I would like to use the grid with jcon=40 but I am not sure it is a good grid, maybe you can tell me after seeing the plot? Thanks in advance, I think I am very close to the solution though now. Just need to know whether this grid with jcon=40 is fine.Kind regards,Amanda

 

[zdliu]

Dear Nan,I want to get the NCL script that can read the binary KMT and grid files and write them back out in NetCDF ,which you put at the website : https://www2.cesm.ucar.edu/working_groups/Paleo/docs/paleo-documentation/convert-binary-kmt-netcdf  But I failed to get, so would you give me a new address/website ? Thanks.----------------Zedong LIU
Physical Oceanography Laboratory
Ocean University of China
238 Songling Road
Qingdao , Shandong 266100
P.R.China
Email:zdliu@ouc.edu.cn

 

[nanr]

Here is the correct link.-- https://www2.cesm.ucar.edu/working-groups/pwg/documentation/cesm1-paleo-toolkit/how/convert-binary-kmt-netcdfn

 

[zdliu]

Thanks. I get it.zedong