CDO

Hi Qiyun,

Steps:

1.) I have downloaded the one fine resolution file. e.g (0.01 degree) then created the Shapefiles according to that resolution using NCL .

;-- copy shapefile_utils.ncl from 
;-- https://www.ncl.ucar.edu/Applications/Scripts/shapefile_utils.ncl
;load "$HOME/NCL/shapefiles/shapefile_utils.ncl" 
load "/Users/kunalbali/Desktop/shapefile_utils.ncl" 

shpname  = "./NW.shp" 
maskname = "./mask_nw.nc" 

print_shapefile_info(shpname)

;-- open data file to get the grid to be used
f = addfile("pm.nc","r")

;-- read variable
var                    =  f->PM25(:,:)
var@lat2d              =  f->LAT
var@lon2d              =  f->LON

;-- shapefile mask resources
opt             =  True
opt@return_mask =  True    ;-- this forces the return of a 0s and 1s mask array

;-- create the mask based on the given shapefile
mask_array             =  shapefile_mask_data(var, shpname, opt)
mask_array!0           = "y" 
mask_array!1           = "x" 
mask_array@coordinates = "LAT LON" 

;-- create new netCDF file and write mask array
system("rm -f " + maskname)
fout = addfile(maskname,"c")

fout->mask_array =  mask_array
fout->LAT       =  f->LAT
fout->LON     =  f->LON

Step:2

remap the your original JRA file according to Shapefiles

cod remapbil,mask_nw JRA.nc regrid.nc

Step:3

mask your file

cdo ifthen mask_nw regrid.nc JRA_mask.nc

Kunal Bali

Hi Kunal,

I see. Thank you very much!
BTW, would you mind to share me your pm.nc file?
Or maybe kindly share with me the link where you download the data.

Regards,
Qiyun

Here is the link

[[http://fizz.phys.dal.ca/~atmos/martin/?page_id=140]]

Kunal Bali

Thank you so much.

Qiyun

Thanks for the help!
I reposted it to Roms Planet