Regridding NetCDF4 in Python

Question

I'm working with various climate models, but right now I'm working on regridding the latitudes and longitudes of these files from 2.5x2.5 to 0.5x0.5, and I am completely lost. I've been running on the Anaconda package for all of my netCDF4 needs, and I've made good progress, it's just regridding that baffles me completely. I have three main arrays that I'm using:

The first is the data_array, a numpy array that contains the information for precipitation.
The second is the lan_array, a numpy array containing the latitude information.
The third is the lot_array, a numpy array containing the longitude information.
All this data came from the netCDF4 file.

Again, my data is currently in 2.5x2.5. Meaning, the lonxlat is currently 144x72. I use np.meshgrid(lon_array,lat_array) to bring lonxlat to go to 72. My data_array also contains 72 elements, thus matching up perfectly.

This is where I get stuck and I have no idea how to proceed.

My thoughts: I want my 144x72 to convert to 720x360 in order for it to be 0.5x0.5. I know one way of creating the lonxlat that I want is by np.arange(-89.75,90.25,0.5) and np.arange(-179.75,181.25,0.5). But I don't know how to match up the data_array to match with that.

Can anyone please offer any assistance? Any help is much appreciated!

Note: I also have ESMF modules available to me.

Answer 1

An easy option would be nctoolkit ( https://nctoolkit.readthedocs.io/en/latest/installing.html ). This has a built in method called to_latlon that easily achieves what you want. Just do the following for bilinear interpolation (and see the user guide for other methods):

import nctoolkit as nc
data = nc.open("infile.nc")
data.to_latlon(lon = [-179.75, 179.75], lat = [-89.75, 89.75], res = [0.5, 0.5])